Chapter Six — I'm Done.

The day after seeing Derek kiss Meredith, the hospital was a symphony of chaos: pagers buzzing, shoes squeaking against sterile floors, voices rising in hurried commands. But to Nate Mercer, it all felt distant and muffled, like he was moving through water. Every noise was too loud, every light too harsh, every patient file in his hands too heavy. The sting of Derek's betrayal throbbed somewhere deep inside him, sharp and unrelenting, like a phantom ache he couldn't ignore.

He'd barely slept the night before. No matter how much he tossed and turned, every time he closed his eyes, he saw it again. Derek in Meredith's driveway, leaning in like it was the most natural thing in the world, like Nate didn't exist. Like the stolen moments between them were meaningless.

It was stupid, he told himself for the hundredth time that morning. Derek had never promised him anything. They weren't in a relationship, hell, they weren't even public. Whatever had been happening between them had been left deliberately undefined, tucked away in shadows and hidden corners of the hospital. So why did it feel like a punch to the gut?

Nate shook his head, clearing the thought as he gripped the patient file tighter in his hand. There was no time to dwell, no room for anger or bitterness in this place. People's lives depended on his ability to keep his emotions out of the picture. Still, his jaw tightened as the memory burned fresh in his mind. He'd been blindsided. completely and utterly caught off guard, and the hurt of it wouldn't let him go.

"Dr. Mercer?"

The voice broke through the haze, pulling him abruptly back to the present. One of the nurses, stood in front of him, holding out a neuro consult. Her brows knit together in concern as she studied his face.

"You okay?" they asked carefully, their tone light but probing.

"Fine," Nate snapped, too quickly, the word cutting out of him like a reflex. The moment he saw the startled look in Olivia's eyes, regret coursed through him. "Sorry," he added, forcing himself to soften his voice. "Rough night."

Their face relaxed slightly, and they nodded in quiet understanding, though Nate could see the sympathy etched into her features. It wasn't pity, he doubted they pitied anyone, but it was close enough to make him shift uncomfortably.

"New consult came in," they informed, handing him the file. "ER overnight. You're up."

Grateful for the distraction, Nate flipped open the file, skimming the notes. A 48-year-old woman, Anna DeLuca, had fainted in her kitchen. A CT scan had revealed what appeared to be a cavernous malformation in her left temporal lobe, a cluster of abnormal blood vessels prone to bleeding. It wasn't the most complicated case he'd ever encountered, but it was delicate. A single misstep could mean the difference between life and death.

Good. This was what he needed. Something to sink his focus into. Something to keep Derek Shepherd and Meredith Grey out of his head.

Nate found Anna in her room, sitting upright in her hospital bed with a wary expression, her hands clutching the blanket draped over her lap. The light from the window cast her in muted shadows, accentuating the faint worry lines etched into her face. Beside her sat her daughter, Carla, a woman in her mid-20s whose tired eyes betrayed a long night of worry. The remnants of tears clung to the corners of her lashes, but she held her mother's hand with quiet resolve, like her grip alone could shield Anna from what was coming.

Nate paused in the doorway for a moment, taking them in, the mother and daughter, the unspoken weight of their shared fear hanging heavy in the room. He adjusted the patient file under his arm, plastering on a calm, professional expression that he'd perfected over the years. It wasn't a mask meant to deceive; it was armor, a barrier to keep the storm inside him at bay. After all, Anna DeLuca didn't need to see the chaos roiling within him. She needed confidence. Reassurance.

"Mrs. DeLuca," Nate greeted as he stepped inside, his voice even and steady. He set the chart on the counter, meeting Anna's eyes with a soft but firm smile. "I'm Dr. Mercer. I'll be heading up your case."

Anna's lips quirked into a polite smile, though her unease was evident in the slight furrow of her brow. "Anna, please," she said, her voice quiet but steady. "And this is my daughter, Carla."

Carla offered a small, hesitant wave, though the strain on her face didn't waver. "Hi," she murmured, her voice soft.

Nate nodded in acknowledgment, pulling a stool over and settling into it beside the bed. He let a moment of silence stretch between them, giving Anna time to adjust to his presence. When he spoke again, his tone was calm, measured, an anchor in what he knew must feel like a sea of uncertainty.

"I've had a chance to review your scans," he began, opening the file in his lap. "It looks like you have what we call a cavernous malformation in your brain. It's a cluster of abnormal blood vessels, and one of them has started to leak. That's likely what caused your fainting spell."

Anna's hand tightened on Carla's, her knuckles paling slightly. "A bleeding blood vessel," she repeated, as if saying the words aloud might make them easier to grasp. "In my brain."

"Yes," Nate said, nodding gently. "It's located in your left temporal lobe. That's the area of your brain responsible for things like language and memory. The good news is that it's a relatively accessible area for surgery, so we can remove the malformation. However..."

He hesitated, not because he didn't know what to say, but because he wanted to give her a moment to prepare. He'd had enough of these conversations to know that rushing through the details often left patients more overwhelmed than informed.

Anna's voice broke the silence, trembling but determined. "However, there are risks."

Nate's gaze softened. "Yes," he admitted, meeting her eyes directly. "Every surgery comes with risks, and this is no exception. Removing the malformation requires extreme precision. We'll need to navigate carefully to avoid damage to the surrounding areas. There's a small chance of complications, such as memory issues or difficulty with language, but the alternative..."

Carla's voice broke in, tight with fear. "What happens if she doesn't have the surgery?"

Nate turned to her, his expression steady but not unkind. "If we leave the malformation untreated, there's a chance it could bleed again. And the next time, it might not stop on its own. It could cause permanent damage, neurological deficits or worse."

Carla's face crumpled slightly, and she dropped her gaze to the floor, her hand gripping Anna's even tighter. "Worse," she whispered, as if the word itself was too heavy to bear.

Anna took a deep breath, her expression hardening with quiet resolve. She looked at Carla, her voice soft but steady. "Honey, it's okay."

"No, it's not," Carla said, her voice breaking. "It's not okay, Mom."

Anna squeezed her daughter's hand, leaning closer. "Carla," she said gently, her tone firm but loving, "I'm still here. And if surgery is what's going to keep me here longer, then that's what we're going to do. Right?"

Carla looked at her mother, tears spilling over her lashes, but she nodded shakily.

Anna turned back to Nate, her jaw set. "Okay," she said, her voice filled with determination. "If surgery's the best option, then let's do it."

Nate nodded, standing and closing the file. "I'll schedule it for this afternoon," he said. "I'll be with you every step of the way, Anna. I promise."

After the surgery, Nate found himself lingering in the attendings' locker room, staring blankly at the open door of his locker. The hum of fluorescent lights filled the silence, his scrubs sticking to his skin after hours in the OR. The case had gone well. It was textbook, almost satisfying, clean removal of the malformation, no complications. Anna DeLuca would wake up tomorrow with no signs of the bleeding that had landed her in his care. Her daughter, Carla, had practically sagged with relief when Nate had told her the surgery was a success. He'd even managed to offer her a faint smile before retreating to his post-op notes.

And yet, standing there now, Nate felt hollow. Empty in a way that no professional triumph could fix. He wanted to feel the pride he normally did after a successful surgery, the quiet satisfaction of knowing he'd done good work. Instead, all he could feel was a simmering anger that refused to dissipate.

The image of Derek and Meredith in her driveway was still burned into his mind. Derek's hand on her waist, the way he leaned in so casually, like Nate didn't exist. He'd spent all day trying to shove it out of his head, focusing instead on Anna's case, but now that the adrenaline of the OR had worn off, it hit him all over again like a punch to the gut.

The door to the locker room creaked open, and Nate instinctively straightened, pulling his mask of professionalism back into place. He half expected it to be Derek, his presence had been conspicuously absent all day, which Nate had been grateful for, but instead, George O'Malley stepped in, clutching a folder and looking slightly out of place.

"Oh," George said, stopping short when he saw Nate. "I didn't think anyone was in here."

"It's fine," Nate said shortly, turning back to his locker. He didn't have the energy for conversation, especially not with one of the interns.

George lingered near the doorway, shifting on his feet like he couldn't decide whether to leave or stay. Finally, he cleared his throat. "Uh, I just wanted to say... nice work on the DeLuca case. I was in the gallery for part of it."

Nate glanced over his shoulder, raising an eyebrow. "Didn't realize you were watching."

George shrugged, fidgeting with the corner of the folder. "Well, I wasn't supposed to be. But, you know, neuro cases are cool. I mean, not cool for the patient, obviously, but, uh, it's just... it's impressive."

Despite himself, Nate let out a small huff of amusement. "It's just surgery, O'Malley. You'll get there eventually."

George flushed, looking down at the folder in his hands. "Still. You make it look easy."

For a moment, the room fell quiet again. Nate expected George to leave, but he stayed where he was, glancing at Nate like he wanted to say something else but didn't quite know how.

Finally, Nate sighed and leaned back against the lockers, crossing his arms. "Something on your mind?"

George hesitated, then blurted out, "The nurses were talking about you earlier. Said you seemed... off."

Nate's expression hardened slightly, his jaw tightening. "Did they?"

George winced, clearly realizing he'd made a mistake. "Not in a bad way! Just, like, distracted. I mean, who wouldn't be, right? Brain surgery is stressful."

Nate exhaled slowly, trying to tamp down his irritation. He knew the nurses meant well, but the last thing he needed was for people to start speculating about his mood.

"I'm fine," Nate said evenly.

George nodded quickly, but he didn't leave. Instead, he hovered near the bench across from Nate, fiddling with the folder again.

"You sure?" George asked tentatively. "Because, uh, if you wanted to talk or anything... I'm a pretty good listener. Or at least, I try to be."

Nate gave him a flat look. "You're offering to listen to me vent?"

George's face turned bright red. "I mean, not vent, exactly. Just, like... if you wanted to, you know, get something off your chest. Or not. Totally up to you. I'll shut up now."

For a moment, Nate considered brushing him off entirely. But something about George's earnestness caught him off guard. It wasn't often that people offered to listen without expecting something in return.

"I appreciate the offer," Nate said finally, his voice softer. "But I'm fine. Just tired."

George nodded, looking both relieved and slightly disappointed. "Right. Of course. You've probably got a lot on your plate. I should get out of your way."

He started to turn toward the door but stopped, glancing back at Nate. "For what it's worth," George said quietly, "you're kind of amazing. What you do, I mean. The way you handled the DeLuca case. Carla said you made her feel like everything was going to be okay. That's... not something every doctor can do."

Nate blinked, caught off guard by the comment. For a moment, he didn't know what to say. "Thanks, O'Malley," he said finally, his voice gruff.

George gave him a small smile, then slipped out of the room, leaving Nate alone once again.

As the door swung shut, Nate leaned back against the lockers, staring up at the ceiling. He still felt raw, the anger and frustration simmering just beneath the surface. But George's words lingered, a faint reminder that, for all the chaos in his personal life, he was still good at his job. He'd given Carla hope when she needed it most. And maybe, for now, that was enough to hold onto.

The hospital felt suffocating as Nate walked down the hallway, the echoes of footsteps around him fading into the background. His mind was a storm, still haunted by the image of Derek kissing Meredith last night. He had tried to push it away, to bury the anger, but every thought of it made his blood boil again. He hadn't asked for any of this. He hadn't asked to get dragged into whatever mess Derek had created.

It wasn't fair. It never was.

What did Derek expect? That Nate would sit quietly while he juggled Meredith and him? That they would just go on pretending this or whatever it was between them was real?

Nate had spent the whole day trying to avoid Derek. He had buried himself in surgeries, in rounds, in anything that would keep his mind occupied. But now, as he walked down a quiet hallway, the last thing he expected was Derek to be waiting for him.

"Nate," Derek called out, his voice soft but commanding, making Nate's stomach tighten involuntarily. "Can we talk?"

Nate stopped in his tracks, his jaw clenching. His fists curled involuntarily, the anger starting to bubble up again. He had no interest in hearing Derek's explanations, his apologies, his excuses. There was nothing Derek could say that would make this okay.

"No, we can't," Nate snapped, his voice sharper than he intended. He tried to brush past Derek, but Derek's hand shot out, grabbing his arm gently but firmly.

"Nate, wait," Derek urged, his voice softer now. "Just let me explain."

Derek moved toward him, his expression softening, though Nate could see the tension in his jaw, the way his hands balled into fists at his sides. He didn't back down.

"I get that you're angry, but this isn't—" Derek began, his voice calm but too controlled, as if he was carefully choosing his words.

"You think I'm angry?" Nate interrupted, stepping even closer. His voice was thick with bitterness now, his chest tight with everything he'd been holding in. "You think this is just about anger, Derek? You've been leading me on, playing both sides like I don't matter, like I'm just some... some backup plan. And then you go and kiss Meredith like I'm invisible? Like us having sex meant nothing? What the hell do you expect me to feel?"

Derek's expression faltered, his gaze flicking to the ground for a second before meeting Nate's eyes again. The guilt was there, but so was something else, something that seemed like regret, or maybe shame. It only made Nate's anger flare brighter.

"Nate, it's not—" Derek started again, but Nate wasn't done.

"It's not what, Derek?" Nate's voice cracked slightly, the hurt rising up in him, raw and unfiltered. "It's not what you think? What is it, Derek? You say we have something, and then you go kiss her. You have the gall to act like I'm supposed to understand this? What, do you expect me to just... sit back and watch you screw everything up?"

Derek's face tightened, but he held up his hands, trying to calm the situation. "I never meant to hurt you."

"Then why are you doing it?" Nate shot back. "Why the hell do you keep pushing me away if you don't want to hurt me? I'm not some idiot, Derek. I see it."

Derek let out a deep sigh, his shoulders slumping in frustration. He looked like he wanted to say something, but the words weren't coming.

Nate could feel the tension crackling between them, but what happened next, what Derek said next, caught Nate completely off guard.

"I—" Derek started, voice cracking slightly, then stopped himself. He glanced around, as if checking to see if anyone was near. When he spoke again, his voice was almost a whisper, and it made Nate's heart skip. "It's more complicated than you think, Nate. I'm still married to Addison."

The words hit Nate like a brick. His stomach dropped, and he couldn't bring himself to say anything at first. For a moment, it was as though everything around him had paused; Derek, the stairwell, the hospital itself, it was all drowned out by the shock of the revelation.

"You're... still married?" Nate echoed, his voice low, like he hadn't even heard Derek correctly. His chest tightened with disbelief. "All this time, Derek? After everything?"

Derek stood there, his face painted with guilt and exhaustion, as if the weight of his admission had just hit him as well.

"I didn't want to drag you into it," Derek said softly, almost apologetically. "But yes, I'm still married to her. And I haven't—" He cut himself off, running a hand through his hair. "It's not like I'm in love with her anymore, but it's... complicated. Things are... complicated."

Nate felt a bitter laugh bubble up in his throat, but he quickly swallowed it down. Complicated. That was the excuse.

"So you're playing me," Nate said slowly, his voice shaking with disbelief. "You're playing me and Meredith and your wife, and none of us even knew it." His chest felt hollow now, the anger replaced by a crushing sense of betrayal. He had been so stupid, so blinded by what he thought was something real.

"No, it's not like that," Derek said, taking a step closer, his voice pleading now. "It's just... I don't know what I'm doing anymore. I never expected this to happen. I never expected you to matter to me again, not like this. But things aren't simple with Addison, and I can't just—"

"No," Nate interrupted sharply, cutting him off. "You can't just leave her, can you? You've been strung out on this mess for so long you don't even know how to cut ties. You never let go of her, Derek. You just—" Nate paused, taking a shaky breath. "You just dragged me into your web, too."

Derek stood there, speechless, guilt written all over his face. He couldn't deny it. Nate could see it in his eyes. He had always known Derek was complicated, but this... this was beyond anything he had ever imagined.

Nate swallowed hard, his eyes burning, his heart aching with everything he wished had been different.

The silence continues Derek clearly struggling to find a way to defend himself, but his words seemed hollow. "I never meant to hurt you, Nate. I didn't mean for any of this to happen."

"Don't even say that." Nate's hands were shaking, but he didn't care. He needed to get this out. He needed Derek to understand the gravity of what he had done. "You meant to hurt me. You just didn't care enough to stop. And now, I'm done."

Derek's eyes narrowed, guilt flickering in them. "Nate, I never wanted to hurt you. I didn't want this to be some... some mess. You have to understand," he begged.

"No, Derek." Nate's voice was sharp, cutting him off. "I don't have to understand. You want me to just let it go, right? You want me to accept that you're a mess and that you're still married, and continue to be used for sex, and that's fine, right? You get to keep playing both sides, and I'm just supposed to be okay with it. But I'm not. Not anymore."

Derek opened his mouth to speak again, but this time, Nate didn't give him the chance.

"I'm not your backup plan, Derek. I'm not a secret, and I'm not some... some placeholder for you while you figure out whatever the fuck you want. And until you figure your messy, pathetic little life out, I'm done. Don't bother me again."

With that, Nate turned on his heel, striding away from Derek without a second glance. His heart was pounding in his chest, every part of him aching as he walked down the hall. The fury was still there, burning, but it felt like the only way to survive this tangled mess Derek had created was to walk away.

He didn't look back. He couldn't. Not when he knew that Derek wouldn't choose him. Not when he knew Derek was still married, still entangled in the lies he was too scared to face.

AUTHORS NOTE.

first off i want to apologise for how short this chapter is as i know they are usually longer. this chapter was so so hard to write, i knew that this confrontation needed to happen between them, and i just didn't want to do it but had to. it was always going to be messy with them.

i hated putting them through this, especially nate, because did derek deserve it? maybe?

nate is finally standing up for himself but at the same time, it's breaking him. he's angry, bitter and so hurt, so he had the right to walk away. derek's been stringing him along, and nate deserves so much better than to be someone's second (or third) choice.

and also addison mic drop, because of course Nate was always going to find out first.

i'm not going to lie to you, things won't be good between them for a while. there's so much resentment and pain between them now, and it's not something that's going to be resolved overnight. nate's not the type to just forgive and forget, and derek, well, let's just say he's going to have to do a lot of soul searching if he wants to fix things.

anyway, thank you SO MUCH for reading and for sticking with me through all this angst. i can't wait to hear your thoughts; what did you think of nate finally standing up for himself? How are we feeling about derek right now? doo we want to hug him or throw him into oncoming traffic? 🧍‍♂️🧍‍♂️let me know in the comments!!