[That's such an innocuous excuse (baking? Really?) that he can't help but give a soft laugh as he steps aside to let her in, glancing down the hall first to make absolutely certain that she wasn't in fact followed.]

It's not exactly "borrowing" if we're both going to be making use of it later.

[Then, as if he hadn't said that at all:]

Take as much time as you need. The bathroom is just next to it if you want to put on any makeup.