The first thing John notices when Rodney slams him against the wall is how goddamn strong he is, and it probably shouldn't be that surprising - Rodney is a pretty big guy, and not actually that out of shape - but it is. John shoves back experimentally against the broad hands and decides that while he could get away, it isn't worth having to hurt Rodney in order to do it. Rodney is not a stupid man - far from it, in fact - and must know this, or he wouldn't have done it in the first place.
The second thing he notices is that Rodney's eyes are very blue, this close up. He notices, too, that this is not the first time he's noticed, and what the hell does that mean, anyway?
Rodney is talking. This is the last thing he notices, because for Chrissake, Rodney never shuts up, but this is different. He isn't yelling about how absolutely stupid this whole idea is, and how only a pack of grade-A morons would risk their ranking military officer on a mission as absolutely certain to fail as this one - well, he's already done a lot of yelling about that in the meeting, and it hasn't made much difference. He's talking in a low voice and as John blinks out of the surprise the words start to register.
"...you already know this is an idiotic idea, so I'm not going to bother telling you again, but I think you should know that if you die I'm not sure my brain can take the strain and they'll have to drug me and send me back to Earth to live in a nice quiet little room where all the staff wear white coats and that would be a great loss for this base and for modern science as a whole and it would be your fault entirely so just." He swallowed. "Don't die."
"I'm not going to die, Rodney," John says in as patient a voice as he can muster. He's still not trying to get away because he wants to know what this is about - but the other teams are already assembled, and he really needs to go, now.
Rodney stares at him for a long moment, and John can feel the heat of his hands even through three layers of clothing, and Rodney's eyes are big and his mouth is half open and he looks so desperate that John figures out what this is about approximately three seconds before Rodney kisses him.
Everything suddenly clicks into place, and John brings his hands up to Rodney's stubbled cheeks and kisses him back because there's no one here to see, because they're in another galaxy, because he knows, as Rodney must know, that there's almost no chance that he's going to get out of this one alive. And anyway, Rodney's mouth is warm and he tastes like coffee and the chocolate bars he has hidden all over the labs, and John curls his hand around the back of Rodney's neck and presses into him until they hear voices at the end of the hall and Rodney jumps back as though he's been shocked. John slumps against the wall, panting a little, as three lab tech hurry past.
"So, um," Rodney says without really looking at him, "good luck out there, Colonel."
"Yeah. You too." Rodney glances up at him, quickly, and he looks so lost that John has to step forward and brush another kiss across his crooked mouth before turning and heading down the hall toward the jumper bay.