Kirk started smacking at the metal door, he couldn't be stuck in a room with Spock, his enemy was sitting only a few feet behind him. Kirk's punches slowed to a halt as his reddened knuckles slide down the frame. "I see you've finally stopped." Spock speaking had pulled Kirk out of his angered daze, only leaving the thought that he had to spend god knows how long in here with him. Kirk turns to face Spock, his cupped hands laying comfortably in his lap, his eyes looking through Kirk, though Kirk still got the anxious feeling that Spock was staring at him. "You know I fucking hate you, right?" Kirk manages to mumble through his gritted teeth, "Yes, you have mentioned it many times, Captain." Spock responds, deciding to look around the room to avoid Kirk's gaze. Kirk didn't know how or why, but a sudden rush of anger flooded him and he ran over to Spock, using all his might to make the connected punch hurt as much as possible. 

Spock fell back from the sudden blow to his cheek, sitting up, he saw the captain in a state of rage he had never seen before. Kirk lunged at Spock but before he could get another blow, Spock grabbed his fist and slammed him against the ground. Kirk's faded yellow sleeve fell to his forearm

And there it was...

The cuts.

Spock's grip loosened as he stared at the deep cuts in his wrist, it startled him that the Captain could be so depressed and hide it so easily with his enthusiastic ego. He slowly let go of Kirk, letting him sit up, Spock didn't understand, but he felt bad... Extremely bad. "Maybe... We can be friends? It may help your self-esteem?" Spock suggests, the warm smile that Kirk gave him, well, Spock knew he agreed

That's how it all started.