By the time she finds him, Dean has gotten the cookies for Jacob--and some for himself while he was at it--and was basically wandering the store to kill time and see if anything jumped out at him as something they needed.

He sees her from the corner of his eye and looks over at her. "All done, or should we hit someplace to get you some boots?"

He thinks it's probably safe to assume she'll want to give Amy her shoes back sooner, rather than later. Wearing someone else's shoes or boots tends to be annoying, since they've adjusted to be comfortable for the owner of said footgear, rather than random other people.