[ She snaps her fingers at his words, like an idea just came into her head. ]

Okay, so it's cleithrophobia instead of claustrophobia, a fear of being trapped. If you ever get trapped and no one else is around, you could try to get out your phone and text... anything, to me. It can be complete gibberish, and I'll know to come find you and get you out.

[ And maybe this won't work if he's trapped without his phone, but she has a plan for that. ]

If I don't at least see you around for a whole day, I'll come find you. [ They live on the same ship for now, so even if they don't talk every day, she does spy his head of blond hair walking around. ]