Bones had never planned on anyone finding out, not even Jim. Of course, Jim had a way of getting people to confide in him, so it really shouldn't have surprised him when he eventually told Jim at least part of the story. That had turned out for the best, and he liked having a friend he could talk to about his past for the first time in far longer than he cared to remember. That didn't mean that he wanted anyone else to know, though.
But fate had always been a bitch, at least to him, and he didn't have much of a choice if he wanted Jim and the others to survive. Mostly Jim, who was lying on the ground unconscious, bleeding from more places than he wanted to think about. He was stable for the moment, but he desperately needed medical attention on the ship. And the Klingons who were responsible for his condition weren't in any hurry to do anything but watch the great Captain Kirk die slowly in a pool of his own blood while the away team watched helplessly.
The whole landing party had been disarmed, their communicators taken, and Spock had a badly broken leg, which meant that the only way they were going to get out of this alive was for him to utilize the skills that he had tried so hard to forget after Olduvai. He'd become a doctor in order to save lives, and now he was going to have to take lives in order to save others.
He sighed, closing his eyes for a moment to focus. Then he slowly rose to his feet and stalked towards the Klingons, Leonard McCoy slipping into the back of his mind and letting John Grimm to the surface for the first time in decades. He ignored the hissed questions from his shipmates, all his attention on the beings that he was about to kill.
The leader of the Klingons looked over at him and laughed. "What are you doing, Doctor? Coming to plead for mercy for your captain?"
He bared his teeth in a feral grin, rocking slightly on the balls of his feet. "Right now, pal, I'm not a doctor. I'm the Reaper." An instant later he was moving, fist coming up to smash into the Klingon's nose while his other hand reached for the knife on the Klingon's belt.
Once he had the knife in his hand it was over for the Klingons. He was just a little too strong and a little too fast, and way too pissed off, and any injuries they managed to give him were shrugged off as if he hadn't even noticed them. Nothing mattered except for removing the things that were keeping him from saving Jim.
Five minutes later he was the only one left standing, all ten Klingons lying on the ground either dead or dying. He knelt next to the Klingon leader's body, absently wiping the blood from the knife as he searched for a communicator. Once he found it he called the ship for an emergency beam-up, completely ignoring both the shocked silence practically radiating from the others behind him and the blood that covered his face and hands.
He'd deal with questions after he was sure that Jim was going to survive.