The Doctor turned to the fuming brunette.

"What do you keep in here? Why have you got zombie creatures? Good guys do not have zombie creatures. Rule one basic storytelling!" Clara yelled. She hit the Doctor again.

"Not in front of the guests," he told her.

Clara turned to them. "Who are they?"

"Friends. Well, people who aren't trying to kill us, so I don't need punching again."

Clara stormed away from the Doctor.

"All right, all right. Look, a deal's a deal. You got the girl and your daughter back. Now cancel the self-destruct," Gregor said.

"Ah. Ah. You know, I've got to tell you, I won't be needing you in my quiz team."

"What?"

"There is no self-destruct. Hey? Hey? Hey? Had you going though, boys, didn't I? I just wiggled a few buttons. Yeah, the old wiggly button trick. And the face. You've got to do the face. Save her or we all die. I thought I rushed it a bit, but..."

"Pretty good bluff if you ask me," Elise said.

The Doctor turned to her and smiled. "I know, right?"

"So you're telling us we're safe?" Tricky asked.

"Ish. Apart from the monsters and the TARDIS reinventing the architecture every five minutes. Guys, don't worry. The countdown's a fake. Look, just give me a second. I'll turn it off. I only made it look as though the engine was actually exploding." He walked over to the console and pressed a few buttons, only for an alarm to start going off. "Ah. That's not good. Okay, don't panic. Or maybe panic."

"Something you want to share with the rest of us?" Clara asked.

"It appears the engine is damaged. We're in trouble, Clara. Proper trouble. It needs fixing or we're toast."

"So now would be a good time to use that big friendly button, right?"

"Yes. Sorry, I should have had one built in." They all ran down the stairs and the Doctor soniced a panel.

"Where are we going?" Tricky asked.

"Detour. The center of the TARDIS."

The Doctor soniced as they walked through a corridor.

Something ran through the corridor in front of them.

"Shush. Something's in here," Clara told them.

"Those things, they've followed us," Tricky said.

"Doctor, what are they? What aren't you telling me?"

"Trust me. Some things you don't want to know," he said.

Something ran through the corridor behind them.

"They're on the move again," Gregor said.

"Run. Move, move!" the Doctor yelled.

They ran through the corridor until they came across Clara who was standing in front of a copy of the Doctor.

"Clara, stop. Don't touch it," the real Doctor told her, "There's a rupture in time somewhere on board the ship. A small tear in the fabric of the continuum. It must have happened when the TARDIS was pulled in by the salvage vessel. The TARDIS is leaking."

"Leaking what?"

He grabbed her hand and led her away. "The past. You and me. Everything we've done, everything we've said. Recent history. It's not real. It's a memory."

The three of them came across one of the creatures.

"What about this?" Clara asked.

"If you're giving me the option, I'd say this one's real," the Doctor said.

They turned and started running, the creature chasing after them.

"She's right on to us."

"She?" Clara asked.

"Clara, don't ask me anymore."

The memory of the Doctor and Clara walked by.

"You're like one of those guys who can't go out with a girl unless his mother approves."

"It's important to me you get along. I can leave you two alone together."

The creature chased after the memories.

There was a loud banging noise.

"What's that noise?" Clara asked.

"We're right under the primary fuel cells," the Doctor said.

"So? So, so what?"

"So, so the fuel's spilled out, so the rods will be exposed. Means they'll cool..."

"And start to warp."

"And start to warp. Maybe even..."

"No, you don't say it. Don't you dare say it."

"Maybe even break apart."

A rod flew through the walls just in front of them.

"You just had to say didn't you?" Elise asked.

"Run?" Clara asked.

"Uh yeah."

"I'm liking how you're thinking," the Doctor said.

"They started running as more rods came flying at them from different angles. The Doctor kept a close eye on Elise. She was not dying today. They heard someone scream.

Tricky was pinned to the wall by a rod going through his shoulder. "Cut it off. Just cut my arm off," Tricky told Gregor.

"No."

"It's the quickest way to release me. No fear, no hate, no pain. I can get a new one. Disposable parts. Just do it. It won't hurt me."

"Tricky, you just don't understand."

"I'm an android. Cut me! What's the matter with you? Why won't you cut me?"

The Doctor tried to help Gregor pull the rod out, but it wouldn't work. "Tell him," the Doctor said.

"Tell me what?" Tricky asked.

"You can't, can you? You're a coward. You won't save him, but you're scared to tell him why." He knew how Gregor felt. He'd felt the same way before he told Elise what had happened to their planet and everyone on it.

"What's he going on about?"

"Robots don't need blast suits. They don't need respirators. They don't get frightened of monsters in the dark."

"What's he talking about?"

The Doctor soniced Tricky. "Two bionic eyes and a synthetic voice box. But you, my friend, are human. Flesh and blood."

"It was a joke," Gregor said.

"What?" Tricky asked.

"It was just a stupid joke. We did it to relieve the boredom."

The Doctor could tell by the look on Elise's face that she was about to have one of her meltdowns.

"A JOKE?! He's a human. Flesh and blood just like you are! How would you feel if someone changed your whole identity just because they were bored!" Elise's face was red and she was panting.

The Doctor walked up to her and put his hand on her cheek, kissing her temple. For once, she didn't push him away.

"I'm sorry. You're human, Tricky," Gregor told him.

"Cut the metal," the Doctor said, "Cut the metal! Go!"

"Where are we?" Gregor asked as they stopped outside a door.

"Power source. Right, you lot, wait here. I'll check it's safe. We can only survive for a minute or two in there," the Doctor said.

Clara tapped him on the shoulder and he turned. "Er, what happens if we stay longer?"

"Our cells with liquefy and our skin will start to burn."

"I always feel so good after we've spoken."

"Marvelous. Keep this door shut."

"That will not be a problem."

The Doctor entered the room and Elise followed after him. "What are you doing!" he yelled.

"I am not about to let you die on my watch."

"I'm your father! I'm supposed to keep you safe! Not the other way around!"

"Yeah? Well get used to it!"

The Doctor groaned. "Fine!"

They didn't have time to waste on arguing.

He ran over to the other side of the engine room and soniced a door open.

They ran back out into the corridor just in time to see Tricky attack Gregor.

"Stop! Tricky, listen to me. Ask yourself why he couldn't cut you up. He has just one tiny scrap of decency left in him, and you helped him find that, okay?" the Doctor said. He turned to Gregor. "Now you. Don't ever forget this."

The Doctor and Elise led them into the engine room.

"Okay, move, move, move. The Eye of Harmony. Exploding star in the act of becoming a black hole. Time Lord engineering. You rip the star from its orbit, suspend it in a permanent state of decay. This way, quickly."

They ran to the door on the other side of the room, but there was a creature behind the door. Another one was blocking the door they just came through.

"There's no way out. We're trapped," Gregor said.

"You're going to tell me right now!" Clara yelled as the Doctor grabbed her hand, "If we're going to die here, you're going to tell me what they are."

"I can't."

"Tell me. What's the use in secrets now?"

The Doctor cupped her face in his hands. "Secrets protect us. Secrets make us safe."

Clara threw his hands off of her. "We're not safe!"

"Sensor detects animal DNA. Human core element. Calculating data. Calculating data."

"No, no, turn it off!" the Doctor yelled.

"Lancashire. Sass. Identifiable substance. Clara."

"That's me," Clara said.

"I'm so sorry," the Doctor told her.

"It's me. I burn in here."

"It isn't just the past leaking out through the time rift. It's the future. Listen, I brought you here to keep you safe, but it happened again. You died again."

"What do you mean, again?"

Tricky and Gregor were trying to keep the door closed from the other creature.

The Doctor rubbed a hand down his face until an idea hit him. "Hang on. As long as we can interrupt the timeline, this can't happen. Don't touch each other, otherwise the future will reassert itself." He pulled Gregor and Tricky away from the door and the creature broke in.

It clawed at Gregor's backpack, trying to grab the circuit.

"Gregor, Gregor, let go of the circuit," the Doctor told him.

"Just let it go!" Tricky yelled.

"Gregor! Gregor!"

Tricky knocked the creature off the catwalk.

A conjoined creature and the Clara creature broke in.

"Okay. Er, er..." the Doctor stuttered.

Tricky attacked the conjoined creature and kicked it off the catwalk, causing him to be left dangling.

"Tricky!" Gregor yelled, running over to him.

"Doctor?" Clara asked.

"No, don't touch him, or time will reassert itself," the Doctor told them, but it was too late.

Gregor pulled Tricky up onto the catwalk and they transformed into the conjoined creature.

The Doctor, Clara, and Elise ran past them to the engine room.