You should not have to explain this to anyone!!! I too struggle daily with my flashbacks and you many people do not understand, but they do not have to understand, because I myself do not understand half the time. Just tell them that you are a very busy person and you are thinking about other things when you disassociate that is what I do. I say, "I'm sorry, what was that, I was thinking about what I need to pick up at the store when I leave work." for example. I know it's not easy, but it is just an example.

And you can always come here. We do understand.