Jack and Michael are driving. Vaughn has been abused recently, by terrorists. He's a little broken and shell-shocked.
V, abruptly: Talk to me. I want a connection.
J, after a pause: I know that feeling. If you have a connection and then lose someone, it's like a Siamese twin being severed. The more connections you have, the more wounds. The more pain.
V: I want the pain. I want that kind of pain. Not this numbness or a--a pain that's just my own.
Jack talks in concise, measured cadences. Almost a monotone, until you begin to listen to inflections. Many pauses between bursts of speech, like cars stopping and then rolling forward at a toll booth in regular intervals, thoughts holding a moment and then releasing. Like his speech, his face is almost flat, but it's not really. It has the subtle topography of a prairie. The stone face of a farmer whose only certainty is that the success of a crop is never certain.
V: I can never tell what you're feeling.
J: Thank you.
Any time Jack seems uncertain the world goes unstable; cracks appear in the ground beneath Vaughn.
After several missions that test their working relationship, a trust builds grows up between them. Jack is loyal--to those he chooses to be loyal to. There's a line. On one side is Sydney and anyone else that he's selected as deserving; on the other side is the rest of the world. So a point comes when he moves that line to let Vaughn in. The rest of the world still remains on the other side.
When Jack expresses his respect and regard, he does it plainly, without varnish. This comes across to Vaughn as almost unbelievably explicit--intense, overwhelming. He thinks that Jack is generous in spirit; kind. Jack denies that he's kind and makes it clear that if he wants Vaughn's company or does anything for him that appears to be above and beyond, it's because Vaughn merits it--it's not kindness.
Jack, flatly: "I'm not kind."
At one point Jack tells Vaughn that he considers him a friend. Vaughn is wide-eyed and touched to the quick; he swallows, doesn't know what to say. However, he's not a woman--no reflex of rejecting compliments or drowning them in nervous blather. He knows how to say thank you in a simple way and mean it.
When Jack feels something for Vaughn, he'd do anything for him. To protect him. He's nearly ruthless when it comes to protecting people he cares for. But he also comes to recognize and respect him as an equal. Recognizes his competence, skill, equilibrium and intelligence.
When Vaughn gets through Jack's defenses, Jack is astonished by his regard, a gift that he accepts, but can't quite accept that he deserves.
Jack talks of his marriage, of trying to figure out how much of her feeling for him was real and how much was false. Was she just a sociopath, or did she have genuine but conflicted feelings for her country and for him? The complete betrayal nearly crushed his heart beyond repair, though he wouldn't use quite those words. (He can be quite naked in his disclosures, though--always startling. He doesn't dress things up, no matter how painful.) And he blames himself because he had suspicions now and then but could never let himself see--out of what he believes to be pride. Ego.
Vaughn tells him it's not his fault, what kind of man would he be if he suspected his wife of being a planted spy? Of being dishonest? He offered his trust. He wasn't the one at fault.
Jack: expressionless, flat, calm, modulated, even-toned, mild, a slight smile. Steady, direct, level gaze. Bland tone. Dry tone. Sharp.
Jack distinguishes Vaughn from Irina--she was very quiet, soft-spoken, mysterious. Vaughn is open, plainspoken, naturally upbeat, grinning, eager, delighted in things. And he's an all-American boy, trustworthy, honest. Once Jack believes that without a doubt, Vaughn has his complete undying regard. No half-measures.
Vaughn doesn't dither or dick around when he speaks. He looks Jack in the eye and says things straightforwardly. That's fairly rare in the agency, and Jack is so used to being dismissive of other people--or considering them only abstractly, assessing their qualities, calculating how their actions impact him--that it takes him a while to really notice and appreciate this quality; to focus on Vaughn and to move beyond an initial reflexive aversion based on his belief that Vaughn and Sydney are growing close. The dad reflex.
The CIA has a list of a hundred exercises for trainee agents, who should tick off as many as possible--posing as a meter reader to get into a stranger's house; stealing something from a shop; waylaying someone's mail, etc. One of them is convincingly kissing someone of the same sex. Vaughn did this during training and realized that he wasn't averse to it, but he would never seriously contemplate going all the way, because he always knew that he wanted to be an agent. Relationships with women have been ultimately unsatisfying so far, though.
Jack has careful movements, is considerate, sometimes unexpectedly so. Polite, well-mannered. Thoughtful. None of which is obvious to people who only have his smooth and deflective professional exterior to go by. Polished, abrupt, dismissive, aloof.
Jack and Vaughn can each cook a little--guy cooking. E.g., Vaughn knows how to do stir-fry; Jack knows how to do salmon steaks.
Vaughn gives him a gift, a copy of The Compleat Angler by Izaak Walton. Jack had mentioned that he fishes. (And owns a cabin somewhere in CA under a different identity that he keeps completely secret.)
Jack's responses are never what's expected--he seems predictable on the face of it, but isn't. If a slight has been made against Vaughn in a meeting by a weasel agent, Jack might respond sharply and publicly humiliate the speaker, or insult him subtly, with a condescending comment and smile that can't be faulted. It all depends on any number of factors, weighed and considered. If he wants something, he might ask the director for it flatly, offering no reason or explanation, or he might angle for it using psychology. As an example, a temporary director wants to put another agent as ops officer on a critical mission, someone not sufficiently a known factor, and Jack wants Vaughn, whom he trusts. He might dispute it in the meeting, butting heads to make a point in what might be perceived as a power play, but instead goes to the director and states what he wants and is prepared for any number of responses he might get, and has contingency plans. He knows roughly what the odds are of various replies and knows how far he's willing to go in any direction to pursue a goal. In a case like this, might even be willing to refuse the mission, let it fail--his conscience would be clear; it'd be the director's fault for making a bad call.
Similarly, at points when he might be expected to control himself and advocate a strict professionalism, he gives in to passion. He has his own views on things that are appropriate and things that aren't, and they don't necessarily align with agency policy. Experience gives him perspective, whereas a less seasoned agent might be more nervous about doing something that could jeopardize a mission. Which is not to say that Jack takes unnecessary or stupid risks--he just may have his own definition of what's necessary at any given time. He can also make mistakes, though. He's not invulnerable or infallible. Just nearly so.
Vaughn was once interested in Sydney, but she became aloof for some reason that was never clear to him, and around the same time he realized that they weren't the best match, temperamentally speaking. He describes her as an amazing person and agent, and he cares about her. Says she's passionate, energetic, focused--says he's not quite in her league, like a plow horse trying to keep up with a thoroughbred. He has no regrets that things never went to the next level. Sydney eventually takes up with another agent.
Jack is at the point where, if he's going to enter a relationship, he doesn't want it to be conducted in secret. Discreetly, yes, but he's either going to decline to discuss his private life if questioned, or tell the truth--everything else in his life can be lies, but not that. He is even ready to quit the agency. Vaughn feels the same way.