Oh, WOW. You capture their laughter. "Dr. Livingstone, I presume!" GORGEOUS! The love, the affection, it's all there. the slapping scene? I love how you set it up as though it were a real blow, and then hit us with the 'love tap' image, and then explain it so vividly we can see it. "Whack the pinata!" And all their banter. And Kelly's playing on Scotty's sympathy. And oh, "Sir, I don't know what kind of establishment you think this is, but..."
Your use of timing and grasp of the development of a scene is wonderful, too:
"That was no truck, Homer. You just got your butt handed to you by Heidi," Scotty said, standing with his arms crossed, not offering to help him.
That body language is the beginning of a sequence that ends three paragraphs later. and the image - of Scotty as a stern trainer, a hard taskmaster, not putting up with any *searches for word* laxity from Kelly, *reflects* the rest of the story, is a parallel to it, in this little section right here.
"Hey, that guy happened to be very tough!" Kelly said, while trying to take weight off his leg.
Aw, I can hear Culp's voice and Kelly's whining!
"Yeah, you really ruffled his pigtails," Scotty said sardonically.
SHRIEEK!
"I don't suppose your humiliating defeat has anything to do with how you went out with the glamorous Yvonne last night instead of staying in and resting up like I told you to."
*snorfle* Love your Scotty's adjectives! Humiliating! glamorous! And his parallel prepositional verbs! "Staying in and resting up"
Kelly glanced back at his Swiss opponent, who didn't even look out of breath, but instead was as apple-cheeked and fresh as if he'd just been yodeling through the Alps.
giggle. What I adore here is Kelly's thorough resentment that just seeps through every word you write in his PoV here.
He turned back to Scotty, putting on as much dignity as he could. "I plead the fifth."
Scotty finally cracked a smile [Oh, and so do we! But I love how Scotty's smile is something Kelly has to work for... although, and this is a big although, you make the affection beneath the sternness palpable. We can see that he's dying to melt, he just won't do it and let his training go soft.] and let his hands fall to his side [Yes! Body language! He relents!] before offering a supporting shoulder to Kelly. "You're a disgrace to the uniform," he said.
Oh, oh, the bantering words, the oblique reference to their shared service, and the shoulder...
You have their banter down to a T. Exhibit A:
"So, I've been thinking," Kelly murmured into the shoulder beneath him, edging down in a slow slide of lips and teeth.
"Don't hurt anything," Scotty replied, broad hands finding their way up his thighs to cup his ass, bracing him to grind up into his hips.
"That'll do from the peanut gallery," Kelly said before biting a nipple, his own thigh falling between Scotty's legs, doing his own moves of this dance.
"Sorry, Soupy. What deep thoughts have been percolating?" Scotty groaned and Kelly wanted to cheer: there were normally few sounds between them, aside from the constant chatter, and making his partner moan felt like a little victory every time.
I love love LOVE the contrast between their banter and the physical moves that follow! But the banter itself - the peanut gallery! That phrase is so much of the era, too! Soupy! Don't hurt anything! *swoons*
And the paragraph that slew me?
As they puttered around their hotel room, making small talk and cleaning their weapons, Kelly mused on the fact that he somehow felt...lighter, recently. It wasn't as if their lives were any less tumultuous or that the next mission might not still be their last. But Kelly found it dragging him down less, weighing on him much more lightly these days, and he couldn't help thinking that Scotty had a lot to do with that.
He laughed to himself as he glanced at his partner. It wasn't even like Scotty was all that great at comforting him: more that at a certain point, he refused to let Kelly wallow in his own misery.
The most amazing, amazing... I've actually known someone like that, but your depiction of it - that amazing pity party and the humorous, yet serious way he put a stop to it - and the *lightness*...