So, for one thing "I have some reservations about trusting her" Uh, no shit, sherlock? You have absolutely no idea who she is, she refuses to tell you anything and she was clearly trying to squeeze you for info. Everything she's done towards you has been hostile. You have absolutely no reason to do what she tells you.
Secondly, given that he's been attacked by psychopath murderers twice in the last couple of weeks (and for the third time in his life), you'd think he would get into the habit of locking his front door.