Yeah, that's fine. [ she might be a little surprised that he feels the need to ask at all, but... maybe he's really not sure that that's what she wants? So Mary quickly adds: ]

It'd feel strange, going home without you, so... it's fine. I'll wait with you for as long as it takes, I promise.

[ It's been awhile since they've done this, but she lifts her head and shifts away-- if just to offer him her pinky. This promise, after all, isn't any less important than the ones she's made to him before. ]