A great deal of what we see between Jack and Irina, sadly, is a game--the game that Irina plays to achieve her goals. Jack is an unwilling challenger, but he plays. He loses, and wins. Irina gets what she wants, but Jack gets what he wants most, Sydney's freedom and relative emotional health. So she's disappointed in her mother. At least her mother didn't leave her standing on the dock with her guts hanging out. Jack took that bullet for her.
But the game requires that much remain unsaid between them. Jack's response to Elsa Caplan indicates his need to express some of his own enormous and pent-up pain and grief. These wounds have never healed and were only reopened and deepened by Irina's return. Yet he could not discuss any of his issues with her because he had to slip into his old role of trusting her as though it were a comfortable old shoe. Is Irina testing him when she brings up her meetings with her case officer at his hotel--is she probing to see if he'd bite back in resentment and pain, instead of the simple sadness she read in his eyes? Yet he needed to test Caplan for Sydney's sake, and it gave him the opportunity to spit out some of the bile that he'd held back so long. No wonder he went farther than necessary.
But not only did he need to hold back for his game; there was also the little matter of the fishbowl that Irina was living in. Jack can have no idea who is watching at any given time, and he is a private man. He certainly doesn't want to air his most private grief and continuing feelings in front of his colleagues, perhaps even his daughter. And he certainly couldn't bring it up during their short time in Panama. It could have ruined everything--and there was hardly time. There is too much anguish, betrayal, and pain between them to be run through in moments, even hours--years would hardly seem to be enough. So when they had the time, he hadn't the opportunity; and when they had the opportunity, they had no time--and there was always the game holding their tongues. So everything remained unspoken.