I actually don't think that was a really bad conversation. I know they hurt and then drive you nuts after, but he managed to calm enough to actually tell you what is going on in his head. You handled it beautifully. Did your C tell you to just walk away when he starts that? Mine suggested going into the bathroom, but to expect to be followed at least the first few times.
My only suggestion, the next time he asks what is going on, just day I don't know. Trying to tell them what is going on, well it is obvious in his answer, you are having a crisis and he is fine. But THIS, what you are doing now, is how you get through this time.
"Acceptance doesn't mean resignation. It means understanding that something is what it is and there's got to be a way through it."--Michael J. Fox
