John never expected it to happen, but he had always imagined that if it did, the setting would some sort of extreme circumstance, a life or death situation. A time when they're both dirty and exhausted and one of them is hurt, struggling to stay conscious—when John would feel his throat close up for a different reason, feel his lips move against his will, following orders of one sort and ignoring others. He's faced certain death more times than he wants to count, however, and although he feels his emotions clenching like a fist each time, he hasn't given himself away.
Which is why, as they both stand in the puddlejumper preparing to unload two full baskets of a bean that very much resembles coffee, John doesn't expect to look over and accidentally let everything he feels show on his face for a brief, heart stopping second—just as Rodney turns to share an open, happy smile.
John can tell the instant Rodney gets it, the flash of realization that shifts the joyful expression on McKay's face from 'We seriously just found the Pegasus galaxy's answer to our dwindling caffeine supply!' to a confused and somewhat searching look.
Forcing himself to turn away, John's mind ramps into overdrive. He scans the details of their mission (nothing there, it had been uncharacteristically friendly), their past week on Atlantis (again, uneventful, not even a minor lab explosion to feign delayed concern over), and finally, their friendship as a whole, looking for an excuse, some sort of justification. Rodney's silence is worrying—but John knows him all too well. He's sure if he offers a logical reason for the rush of affection that had taken him by surprise, McKay will take the bait. Deflect, deter, defend.
John thinks Rodney's voice should sound wary, but it doesn't. He reacts as if it did.
"Sorry, McKay. The thought of not having to deal with grumpy scientists going through caffeine withdrawal almost made me break into song," he says, injecting as much of his internal conflict into the sarcasm as possible. The resulting silence is just as uncomfortable as before, but now John has no idea what would show on his face should he turn around, so he changes tacks. "Speaking of which, shouldn't we be opening the rear hatch to offload—"
With his mind working at Mach three, John's other senses fail him; Rodney's managed to step around their trade supplies to a position directly in front of John. For once, McKay doesn't bluster, doesn't accuse. He just steps forward, looking at John with an expression of hopeful curiosity, rubbing at the palm of one hand with a thumb like he's the one with something to feel nervous about. Then, eyes narrowing as though he's running an experiment (which, John realizes with a caught breath, he kind of is), Rodney reaches out an unsteady hand to rest it, warm and flat, just over John's heart.
John doesn't move, not even to blink, eyes fixed on a point just over Rodney's shoulder as he tells himself he's memorizing the texture of the puddlejumper's wall, not the way Rodney's palm feels against his chest. They stand like that, at a stalemate for a long minute until Rodney brushes his thumb across the fabric of John's shirt in an unmistakable caress. John's self control goes AWOL as he shuts his eyes and lets out a breath. By the time he opens his eyes again, his 'three D's' plan is of no use—the very fact that he hasn't moved away proves Rodney's hypothesis as surely as if John had been the one to reach out.
"Why didn't you ever say anything?" Rodney asks, his voice oddly gentle.
He should say, 'About what?' He should back away, feign tiredness, space flu, something. Instead, John thinks about his first week in Atlantis and the private talks he'd had to have with a few select members of the military contingent about their attitude toward a few of the scientists. He remembers the lines of calculated disapproval on Colonel Ellis's face when John had taken it on himself to defend Rodney's actions to the man. He recalls the many, many times he's told himself that holding back is not only required, but necessary—for himself, for the people under his command, for Atlantis. John looks back to the day he made the decision to join the Air Force and wishes he could claim he hadn't known what he'd been giving up.
He'd known; John just hadn't thought it would hurt so much.
"I don't expect to… I can't fly and have this," he says simply. He expects Rodney to flinch, to pull back where John cannot, but Rodney steps forward, the stubborn lift of his chin as familiar as breathing. They've both already skipped several stages of this conversation; it only stands to reason that Rodney would disregard the part where he's supposed to leave and forget the whole thing.
"Sheppard," Rodney says, his voice low but animated. "We live in the lost city of Atlantis. We regularly fight actual life-sucking aliens. You have a throwback gene that lets you fly spaceships with your mind! And yet, somehow, this" —Rodney slides his hand up to John's neck, raising his eyebrows expressively— "is where you draw the line for realism? 'This far, no farther?' Bullshit."
John opens his mouth to object, but he's being confronted with almost everything he's been wanting, everything he can't have—everything except flying. It all comes down to flying. Flying and Rodney. Before he can get a word out, though, Rodney has stepped forward again with determination, inclining John's head to his and touching their lips together gently once, twice.
"You should know by now," Rodney says against John's mouth, each word making John's resistance crumble out of a combination of sensation and infuriating logic. "Never say 'can't' to Rodney McKay, John."
Rodney breathes John's name rather than says it, and John's hands come up to hold him steady, so that John can taste the word on Rodney's tongue. It's all wild velocity with no inertial dampeners, and all of a sudden John's stupidly grateful for Rodney's stubbornness and his unpredictable bravery, because this is a rush that's comparable to flying, and John's feet haven't even left the ground.