Her initial response would probably be something like, hell no, get your terrifying feet away from my vulnerable house... except for two things.

First thing! She's not some neophyte baby spider any more, of course she's reinforced this structure with fire resistance. Second! He definitely carried her that one time instead of, say, kicking her, which would have been the more rational response to seeing a small lesser taratect dive out of a train cabin. It'd be kinda rude to just kick him out after that. Also, she's still a big fan of his character design. You know, generally.

... Third thing! Her mouth is full, so she can't say anything anyway. She gives him a double thumbs-up instead.