A/n: I wrote this with TOS in mind, but it could easily fit AOS.

Warnings for mature themes and profanity.

Coming Through in Waves

Part I

Spock dislikes doctors.

He dislikes their gloved hands, their whirring tricorders, their faint antiseptic smell, and the way they patronise their patients. Mostly, he dislikes the way they look at him: with that glint in their eye, like he is an exotic cadaver waiting to be dissected. ("First of his kind to survive, mixed breed, just one more time, Spock – ")

Boyce had, for the most part, minded his own business – he cared more for research on human biochemistry than his patients, and Spock was out of scope for him. Spock found this acceptable; he is naturally hardy and did not step off the ship often enough to have any significant threat to his person. Moreover, his claim that Vulcans are too private to freely offer samples had been met with little more than a resigned shrug.

So when Spock walks into his shared bathroom at 0500 hours and finds Leonard McCoy spitting mouthwash into the sink, his first impulse is to quickly retrace his steps into his quarters. But McCoy looks up at him, raises his eyebrows, and says, "Mornin', Mr. Spock," so Spock does the next best thing: he returns the greeting, perhaps more curtly than necessary, and begins to squeeze toothpaste onto his brush.

"You're all bright-eyed and bushy-tailed," says McCoy, stepping aside to give Spock more room.

Spock pauses with his toothbrush right next to his open mouth. "I have no tail," he says, perplexed. He almost considers turning around and checking, but since it will be an affront to his dignity, decides against it.

McCoy chuckles, his voice still gravelly with sleep. "And they say Vulcans have no sense of humour."

Spock does not reply and begins to brush his teeth, hoping the human will go away. For the first week, he had not encountered anyone in his shared bathroom, so he assumes McCoy's timings are erratic, and he will have to memorise them to avoid him. Jim had wanted them to be friends ("Mr. Spock, come here! This is Bones – Dr. McCoy! An old friend of mine!" McCoy had replied, smiling, "Unfortunately."), but Spock, on principle, will not befriend medics. They are interfering and inefficient and self-absorbed (he wonders if it has anything to do with them studying the biological self rather than the workings of space). It is logical to give them a wide berth.

When McCoy yawns, scratches his hair, and returns to his own quarters, Spock relaxes.

Avoiding McCoy, however, turns out to be more difficult than he had anticipated. At the mess hall at lunch, when he is sitting with his captain, Jim waves over McCoy, almost knocking over his orange juice in his eagerness (he has been over-excited since McCoy came onboard. Jim's efficiency, Spock notes with distaste, has dropped by 0.12 percent. Obviously, McCoy's presence is detrimental to the functioning of the ship).

Just as McCoy sits down, Spock stands up. Jim looks at him quizzically. "Mr. Spock?"

"I have reports to write, Captain," says Spock. "If you will excuse me." He walks away, the weight of Jim's confused gaze heavy on his back.

When McCoy comms him the next day for a physical, Spock gives a vague, noncommittal answer, and then ignores him. He had done the same with Boyce, who had forced a quick blood sample from him to placate the brass and never bothered him again.

McCoy comms him thrice more, and Spock only answers because the incessant calls are beginning to give him a headache. Before he can open his mouth, McCoy says, "Spock, get your pointed ears down in sickbay before you die of some endemic brain disease you pick up from your next planetside mission," and cuts the line. Spock is left staring at the comm, agape, and wondering how such a boorish, unseemly man was ever recruited by Starfleet. (For a moment, he entertains the idea that Jim pulled McCoy in because they are friends, but discards it; even disregarding Spock's own admiration for the man, Jim would never jeopardise the safety of the crew.)

But when he informs Jim, his captain laughs. "Oh, Bones is just a cranky old teddy bear," he says. "Do as he says, Mr. Spock. Make me happy."

Spock mouths 'cranky old teddy bear' under his breath as he does as told, wandering into sickbay just as McCoy finishes administering a hypo to a redshirted ensign. "I was wondering if I'd have to haul your backside down here myself," McCoy says, letting the ensign scurry off.

"Vulcan bone density is three times that of an average human male," replies Spock, imagining this brittle slip of a man trying and failing to heave him over his shoulders. It is unexpectedly amusing. He quashes the feeling.

"From what I've read," says McCoy, hunching over his computer and squinting at the screen, "you're half-human, so your bone density is...unknown." He frowns. "How could Boyce even call this an examination? It's so facile." He bounces on the balls of his feet – a gesture that is unprofessional and vulgar. "And I believe you're the first of your kind to survive?"

Your kind. Spock stiffens. "What of it?"

"It means I've got a truckload of extra work on my hands, trying to keep you from dying."

Spock is surprised, though he hides it. He had not been expecting concern, even if misplaced. "I assure you, Doctor, your leeches and rattles will be unnecessary. I remained healthy throughout my tenure under Captain Pike's command."

"That doesn't mean you're gonna stay healthy under Captain James T. Kirk's command," McCoy returns. "That kid attracts trouble like flies to honey. And leeches and rattles? You've got a lot to learn about modern Terran medicine." He balks, cocks his head to one side. "Are you tellin' me you never went for your physicals before?"

"I went once." For the blood sample.

"And Boyce was okay with this? Starfleet Command was okay with this?"

Spock blinks at him, unwilling to speak further.

McCoy bounces a bit more, turns red, scowls, stills, and takes a deep breath. What he calls Boyce, Spock would never repeat in polite company – or any company. "Well, Mr. Spock," McCoy gives a long, loud sigh, "it's not gonna be that way with me. You'll need quarterly physicals and regular hypos. And your first physical is gonna take a while, because your body is a blank slate to me. I effectively know nothing about you."

And I would prefer to keep it that way, Spock thinks, but holds his tongue because it would not go down well with Jim.

McCoy is speaking. "Are you free now?"

It is best to get this over with. "I am."

He tolerates it. At the very least, McCoy does not get too close, does not engage in casual touches, and steers clear of Spock's hands. This, Spock is grateful for; he has already had several people (including, embarrassingly, Jim) hold his hands. The first time, he was so shocked he could not protest.

McCoy punctuates the session with little exclamations, "Wow" and "Really?" and "Dear Jesus, Muhammad, and Zoroaster..." Spock is unsure of how to react to this; McCoy is clearly intrigued, clearly taken aback, but not invasive. The entire process is less painful than Spock had expected, though he harbours no liking for it or McCoy. When it is over, McCoy mutters, scribbling on his PADD with a stylus, "Thank you, Mr. Spock. I'll see you in three months."

"We share a bathroom," Spock says, before he can think the better of it. Neither of them needs the reminder; they are a most unsuitable match.

McCoy looks surprised, and then smiles. "So we do. Hopefully, we won't walk in on each other taking a shower."

"I find that idea most unpleasant."

McCoy chuckles and turns away. "All right, get out of my sickbay, Commander."

Spock raises an eyebrow. "You are aware I outrank you?"

"Out."

As Spock leaves the sickbay, he ponders on whether or not he should officially file a report on insubordination. Something – nothing so illogical as intuition, but a set of information his brain is taking in too fast for him to process – is telling him he is misunderstanding something. Some integral part of how humans behave. Particularly how this wayward, improper human behaves.

He decides against filing the report, considers it an exercise in understanding human psychology for his own ability to function with the rest of the crew.

Jim insists on bringing McCoy along with the landing parties. Spock tries to tell him it would be more logical to bring a nurse or another doctor, as they cannot afford to lose their CMO and it would be a shame if McCoy accidentally dropped off a cliff or got his head chewed off by the local fauna. It is a sound argument, and Spock does not wish to be near the man who knows more about his body than does anyone else on the ship, but Jim cheerfully brushes him off and orders a sour McCoy onto the transporter pad.

The planet is M-Class, and where they stand, the temperature is negative two Celsius. Copses of trees with plum-coloured leaves stand vigilant here and there, and there is what appears to be a forest 342.7 yards off. Spock is discontent in this weather, though Jim grins even as he blows into his hands.

They split up; Jim with Giotto, and Spock with McCoy. Spock gives Jim a baleful look as they head off in different directions; McCoy seems like a man with a sound sense of self-preservation, and surely would be of no help in the case of an attack. Jim possesses fine hand-to-hand combat skills, but is also prone to heavy injuries, and while Giotto is an adequate security chief, Spock would be more at ease if he himself were by Jim's side; his quicker reflexes and denser body mass give him an advantage in hostile situations.

McCoy seems intent on being a nuisance. After they enter the forest, he keeps asking Spock irrelevant questions as he skips along, occasionally kicking stones out of the way: So what's your family name? How come you didn't want to work at the VSA? Are the ship's temperatures too low for you? When Spock remains silent, taking readings of the elongated green berries of a bush, McCoy rolls his eyes and grumbles to himself, fiddling with his tricorder. Spock will never understand the human need for 'small talk', and McCoy seems prone to that vice.

He raises his eyebrow at the readings. That is an unusual level of ethylene –

The shower of arrows is unexpected. One embeds itself an inch above his head in a tree, and from the corner of his eye he sees a small group of what are probably natives, white-skinned and pale-haired, clad in skins and horned helmets, charging towards them with war cries. Five of them, tall as young trees and stocky. Spock whips out his phaser and fires a warning shot at their feet. They do not even blink.

In his shock and dismay, he begins to wonder if Jim has encountered trouble of a similar sort.

"Spock!"

Spock turns around just in time to see McCoy stagger and hit the ground hard beside him. An arrow sticks from his side, and Spock watches, with a type of numb horror, as McCoy curls up uselessly in instinctive fetal position. Punctured lung. Spock's own body moves on autopilot. He drops to one knee beside McCoy, flips open his communicator, and snaps, "Mr. Kyle, two to beam up, now."

As they materialise back on the Enterprise, Spock's brain runs at a mile a minute, even as he orders a medical team to the transporter room: why would he why did he what is wrong with him what –

He barely notices McCoy being placed on a gurney and rushed through the doors. Deep breaths help calm him down. Now, he understands a little of Jim's ire when Spock takes a shot for him. Guilt and shame bloom hot in his gut. He should have been more on guard. He should have been quicker in his thoughts. He should have protected his weaker human shipmate.

His command stripes glint in the sickly light. He shakes his head, suppressing his thoughts. He is an officer, and he will match Starfleet's standards till he dies. Flipping open his communicator, he prepares to give Jim a report.

Seven hours and forty-two minutes later, in sickbay, when McCoy opens his eyes blearily, Spock says by way of a greeting, "That was illogical of you. As CMO, you are less dispensable than First Officer, and now the captain has reason to reprimand us both." McCoy does not need to know that Spock has been checking in every hour after the surgery. He was not concerned; the ship cannot afford to lose medical personnel, and Jim would not have borne the news with his usual equanimity.

McCoy groans, his hand coming to flutter over the patch where his wound is. His fingers are long and square. "Uhh, go sit on a porcupine, Mr. Spock," he says, and promptly falls back asleep.

Two weeks later, Spock has the unlucky privilege of watching McCoy instruct a group of trainee healers in a simulation of a medical emergency with limited equipment. Jim stands by his side in the observation chamber, trembling with what Spock suspects is suppressed hilarity. Chapel breezes through the room with serene stoicism as McCoy barks orders and hurls insults amid a maelstrom of rudimentary medical equipment, volunteer 'casualties' who clearly cannot act, and fake blood and gore.

"Radcliffe, that's his subclavian artery! Are you trying to kill him?"

"Why are you just standing there? There's a man going into haemorrhagic shock in the middle of the room! No, Gokhale, what – "

"Daruwalla, you don't use a tourniquet like that!"

"What the hell's happening in here – brain surgery? Move it!"

"Are you fucking serious, Kondou?"

By now Jim is covering his mouth to muffle his laughter and has tears in his eyes. Spock looks at him with disapproval; Jim had not struck him as one who took pleasure in others' pain. "Captain, is it necessary for the doctor to be so…" Emotional. "…harsh?"

Jim looks at him, sobering but still smiling. "I'd like to say no, but yes, he does. Being a doctor is in one of the most stressful and demanding jobs in Starfleet, and treating patients when there are phasers firing and people trying to kill each other even more so. Those trainees aren't children. They knew what they were getting into, and they know what McCoy is doing."

"Trying to unbalance them," Spock says, beginning to understand. "Making the simulation as stressful as possible so they are better prepared in real circumstances." It is not necessarily a method he approves of, or would employ himself, but it is one he can see the logic behind.

In the mess hall at dinner that day, McCoy sits at their table, rubbing his throat and grumbling about losing his voice. Jim grins at him. "Hey, you got to yell at a bunch of greenhorns – same as was done to you. Doesn't that make you happy?"

"You know what, Jim?" says McCoy tiredly, picking up his replicated cheese and cranberry sandwich. The shadows beneath his eyes are always noticeable, but they are more prominent today. Something pangs in Spock's chest, and he realises it is pity, mingled with something like budding, if reluctant, admiration. "It doesn't." He takes a bite, chewing without enthusiasm.

Jim's smile grows softer. "I know, Bones," he says. "Try to get some rest."

McCoy grunts, swallows, and says, in an obvious attempt to alleviate the tenseness, "Radcliffe may need to be transferred to a starbase. He's good, but maybe not cut out for a starship. Gokhale shows a lot of promise – she was a bit nervous, but I've seen her past results…"

Jim watches him with an expression filled with affection, with perhaps something deeper. Spock is starting to comprehend the whys behind their peculiar friendship.

When McCoy, standing at his door with his hair askew, blinks owlishly and says, "Um. Yeah, sure. Don't see where else you can go," Spock is, by turn, taken aback, grateful, and apprehensive. In a moment of rare, cold panic, he almost retracts is request and offers to sleep in one of the science laboratories, but then McCoy yawns and says, "I got a sleeping bag, or you can use my couch, if you like," and Spock finds himself saying, "Thank you, Doctor; I will use the couch."

There had been a run-in with a Klingon warship, and a bomb had been planted on the senior officers' floor. Spock's quarters had taken the worst of it. Needless to say, he does not have a place to sleep. He had considered requesting to stay in the captain's quarters, but then decided it would have been too audacious. (And there is a small, mostly suppressed part of him that wants to know more about his firecracker of a bathroom-mate.)

Spock moves his remaining possessions (many had been destroyed or damaged in the blast) into McCoy's quarters that night. He expects there to be used clothes piled on a chair, coffee stains on the bedsheets, papers kept with the shoes, possibly a half-empty bottle of brandy on the desk. But everything is stacked into orderly piles; the bed is neat and the floor spotless. The couch has a pillow and a blanket folded on it. There is even a glass of water on a small side table.

With some regret, Spock realises he had not considered how his timings would affect McCoy, so he asks, "Would you be disturbed if I worked during the night? I can work in the laboratories and return when I am finished."

McCoy does not look up from where he is making his bed. There is a soft slope to his shoulders that speaks of too many hours hunched over in a chair. "No, I'm more likely to wake up if the doors swish open. You can stay here."

Still, Spock has adequate energy, so he stays up conducting experiments in Laboratory 6 – McCoy will have some time to adjust to the change. No doubt seeing Spock's possessions in his quarters is jarring enough.

The second night, he stays in, tells himself there is no reason to be self-conscious. While reviewing his junior researchers' papers on astrometry, Spock reaches for his tea, and his fingers meet air. He looks up, blinking, and then remembers that his stash of tea from ShiKahr had been destroyed in the blast – no Earth tea has quite the same taste or properties. Still, he desires a hot drink, and hesitantly asks McCoy if he has any decaffeinated infusions, though McCoy does not seem the sort to consume those.

"So now this is a tea shop as well as a hotel?" McCoy says with a wry smile, the hair at his temples still damp; he had been washing up in the bathroom. Spock's stomach feels strange, as if he has jumped from a height. Then the sensation is gone. Odd. If it happens again, he will have to consult McCoy.

McCoy puts the kettle on and gets a tin from a drawer. When he makes the tea, there are no extra movements, no fidgeting, and when he hands Spock his steaming cup, he bends slightly, as if over a patient, his expression both remote and kindly. Spock wonders if McCoy knows how to not be a doctor, even when he is not treating someone.

While Spock sips at his tea (blackberry – tart but refreshing), he finds himself distracted, casting furtive glances at McCoy, who is sitting in his bed, perusing something on his PADD through a pair of round spectacles that are gradually slipping down his nose. He is engrossed in whatever he is reading, moving only to rub the faint stubble on his chin or swipe the screen.

McCoy is not a handsome man. He is awkward and well into middle age and his face is worn with care. But there is a charm to him, in the narrowness of his waist, in his way of hopping or skipping instead of just walking – a strangely carefree, though not unwelcome, habit in an organisation as austere as Starfleet. He is not weak, but he has an air of gentle vulnerability that is appealing. Is that why their enemies usually target him first? Spock has noticed their disturbing tendency of not just singling him out, but of toying with him, of deriving pleasure from his frustration and pain.

Spock realises he is staring, and also not focusing on his work. He returns his attention to his papers, his toes curling.

Notes:

1. Let Bones say fuck.

2. Spock: "Allow me to point out that a first officer is more expendable than either a doctor or a captain."

Jim: "Officially, yes ... "

- 'The Cloud Minders', S3 E21