Hello housemate!! Edward's presence isn't especially comforting but once he cottons on to the general vibe of the place he'll be making a point to try and give Beth some space (couch-sleeping, leaving the living room if he gets some impression she wants the tv, etc). I think her age + not being a visibly asskicking type will make him more willing to believe she's another ?kidnapping victim? instead of a captor, and consequently someone he doesn't want to freak out. He'll probably try to pitch keeping a journal hidden somewhere to take notes on anything that seems significant + doing some introductory Q&A (half of his answers will be lies) since they're probably going to be stuck together for some time.

He'd be able to run with pretty much any reaction, up to and including getting the 'imminent threat' treatment - by all means Beth, punch him.