It's his tone of voice rather than the lack of weaponry that convinces her - after all, he didn't use a weapon last time.

"You should come in, I have. Um. Chairs. And things. Are you alright? I mean, are you going to be alright, 'cause you're not..." She flails her way through that sentence with a startling lack of coherency, backing away from the open doorway to let him in.

And if she's careful to keep one of her hands out of sight, that's her own business.