It would take a long time. Most of the memory loss is tied to events, right? So to forget everything about home, imagine how many events you'd have to have.

[It isn't that he's not worried about the possibility - the whole experience was eerie and foreboding, and really only made worse by the sleep deprivation. But from his own experience, it isn't something to panic about. Hence his rather neutral response, despite her obvious horror at the whole thing.

Still, there's some melancholy in his expression. After all, he knows this from experience.]