"Oh, no, don't—" he's beginning to say, because having anyone fuss over the books is faintly embarrassing and fully unnecessary, but then he sees her recognize him, and merde indeed. He starts running through his mental catalog of faces: allies, rivals, marks—or the servants of marks, most likely, in the case of an elf—and considering what he will do if it comes to that. Leave, most likely.

But he smiles like it's nothing, and before he's finished trying to place her face, she shakes her foot, and he places that.

(Not in a weird way.)

And that's a relief. He says, "You do," and dips forward a few inches. Not quite a bow, because this is Hightown, and she's an elf, and he doesn't want to draw attention or spark gossip at this particular moment—but the cheerful suggestion of one. "I once collapsed—" slight hyperbole "—trying to keep up with you in a bourrée."