While Wren is indeed busy with her brew behind the counter, she has the greatest of security devices in place so she doesn't miss a customer: a bell on the door. So while she doesn't immedately look up at the girl entering, she's well aware that she's there. Wren will let her look around for a minute or so before finally looking up from her work to greet her.

"Hello! Are you looking for something special today, or simply something new?"

She starts to come out from behind the counter, but the aisles are tall enough and she's moving slow enough that there may be enough time to take a potion off the shelf without her notice. Unless, of course, there are other security measures in place; this wouldn't be the first time someone tried to steal from her shop.