Bones hates space. He hates going into the unknown, where there are diseases that he doesn't know how to fight or some undiscovered force could kill the entire Enterprise crew in the space of a few precious seconds. Death could come in many forms.
Yet he stays on the great hunk of moving metal that cruises serenely through the stars, unknowing of the danger it flirts with every time they encounter another ship, another planet, another life form, an unexplained anomaly.
Bones tries to fight the unknown by vaccinating his crew as often as medically advised, encouraging anyone to come to him with any medical attention needed, and keeping his med bay in shipshape order. Anything that Medical is even the vaguest danger of needing is to be reported immediately. The nurses are the top of their classes in Starfleet Academy, and Christine Chapel is leads all medical staff. Disease is highly guarded against on his ship.
And for the most part, it works. The Enterprise has one of the lowest preventable death counts in the 'Fleet, and Bones is asked to advise other ships on how to mimic his lifesaving methods. He helps the fatality rate of Starfleet fall, and he lives on the Enterprise, grumbling about space every chance he gets.
Until one day, the admiralty offers him a chance to get off the ship:
"You have more to offer the universe as an adviser, consultant, or even a professor than you can accomplish drifting through space, Doctor." Admiral Hepler tells him only two years after the five year mission had begun.
Bones is standing in the middle of a room that's empty except for the Admiral's desk and Hepler himself. The walls are an unforgiving grey, nothing like the light blue walls of his medbay. Bones believes that clean, gentle surroundings can offer a patient an awful lot of comfort, probably more than loved ones throwing themselves everywhere bawling their eyes out and wailing to beat the band.
The Enterprise is on a rare treat of Earthen shore leave after Khan's attack. Actually, it's a very extended leave, because so many repairs have to be made to the flagship that the Enterprise crew is effectively grounded for a three month long vacation. Kirk is on enforced medical leave, Spock is teaching at the Academy, Chekov and Uhura studying to stay on top of their fields, and Sulu is trying to program simulators for a new pilots' course.
It's wonderfully peaceful, but Bones can tell that every one of them is just itching to march right back into the tin can and hurtle once more into space to explore and gain new knowledge.
Never mind the danger that lurked, there was adventure somewhere in the vastness of space, and damn it, they were going to find it.
"Not as the doctor of a starship that I was practically begged to sign on to? Sir." Bones tacks onto the end of his otherwise pretty damn offensive question. Starfleet had been after him since he was 12 and his aptitude tests came back as stellar, even for Starfleet's standards. McCoy was, is, a good doctor, and he knows it. Only the very best were assigned to the Enterprise, and he's proud to call himself one of them. Even if it did take three months of straight drinking after the divorce and before the papers were signed, 3 years of constant study, and more gray hairs that Bones wants to think about.
"In the light of Captain Kirk's recent... Medical miracle, Starfleet has considered the fact that your talents ought to be shared through the universe, so that all peoples and races could benefit, rather than a single ship."
"In other words, you've got no explanation for his sudden recovery, and you want to squeeze it out of me." Bones isn't having any of this higher calling bullshit. "Well, I hate to tell you, but it's just like in the medical report: Captain James Kirk was very close to death, but some good, old fashioned common sense and medical experience, alongside a healthy does of luck, saved him. Hell, ask Commander Spock. Vulcans don't lie." Ha. That was in and of itself a lie. Spock was more than willing and able to lie like a rug whenever it suited him.
"We already have. Commander Spock confirmed your report." Hepler folds his hands on his desk. "This isn't a hidden motive, Doctor. Starfleet is simply asking you to consider sharing your knowledge and improve millions, even billions, of lives."
Bones pauses at this. He hates space. He hates the unknowable. He hates the disease, the death, the uncertainty of it all. He hates knowing that Jim might come back to him in a body bag, and there would be nothing he could do. He hates the idea of his crew under the jurisdiction of a different doctor.
But even more, he hates the idea of his (not the Enterprise's, not Jim's, but his) crew up there in all of it without him. He had known the answer from the first words Hepler spoke.
"I apologize, Admiral, but the answer is no."
Hepler nods, obviously not surprised. "I knew it would be. Best of luck up there. Make us all proud."
Recognizing a dismissal, Bones salutes and heads for the door.
"Oh, and Doctor?" Hepler calls as Bones opens the door.
He turns back. "Yes, Sir?"
"If you change your mind, we'll be happy to have you."
Bones grins crookedly. "I wouldn't count on it, sir."
"I'm not, either." The Admiral cracks a small smile for the first time since Bones was called in.
And Bones steps out of the office, towards the ship, towards space, and he knows that he doesn't hate it.
But that doesn't mean he has to like it.