Jarvis gravitating that much closer to him, coming that much further within his radius of control, helped to ease some of the brittle tension he felt, which was threatening to undermine a bid for trust that really needed to carry the day. Control, after all, was the root of the problem here - it could be dressed up in all kinds of different ways, couched in terms of fear of death or the need to protect what little he had or even an unlikely desire to shepherd in a new era of peace and equality, but in truth the trouble was that he felt like he was one wrong move away from spinning out completely. It made him, to say the least, prickly.
But he didn't need to be - he had this in hand, for now, he reminded himself as he made himself relax a little, standing down from the by all appearances unnecessarily bellicose posture he'd taken with Rogers, settling into his place between the two of them. Rogers's reaction was ... well, it was good. It was helpful. And it was interesting; it said far more about him than anything else Tony had ever seen from him, than any of his refusals to play by the rules, his protestations of shock or disgust, his boneheaded brand of 'courage.' Tony had just handed him the key to his destruction - a couple times over, frankly - and here he was, turning it over in his hands with nothing but admiration, commenting on how very nicely it was made. Rogers was grinning, he was in awe, he was impressed (and that din't hurt, of course - some of Tony's buttons were sadly clearly-labeled in print large enough for even Rogers to read, woefully easy to push). There wasn't one single solitary drop of design or manipulation, here. He was just ... happy.
And he was being polite, a requirement Tony suddenly found he was determined to enforce with an iron fist - not quite fair, perhaps, considering during their last dinner he'd mocked Rogers for doing little more than glancing in Jarvis's direction (never mind his own not-quite-perfect manners), but all the same, those tripwires were set, now, taut between jealousy and protectiveness, and they were on a hair trigger. Woe to him who looked at that man sideways.
He refrained, in his newfound devotion to decorum, from interrupting and performing introductions for people who could do so perfectly well for themselves. It felt like a triumph of etiquette.
"It is possible," he said instead, and didn't add: obviously. "The technology's still a prototype - by definition, I guess. There's only the one. But fifteen years into development, and we're doing - really well. As you can see." It was awkward, a little stilted, stiff; but it wasn't defensive, not quite. Collaborating. "We both know," he added, with a brief glance in Jarvis's direction, "the stakes are very high." He suspected Rogers thought of him as someone with nothing to lose, because of course he didn't seem to possess anything Rogers would value (or hadn't, before today); but the fact was that he valued his own life pretty damned highly, estimated Jarvis's to be worth ever so slightly more, and was really, really fucking fond of all the very nice things he'd accumulated over the years, whether or not Rogers thought they were so much dust. "So why don't we just start from there."