Um..

How do you know where my vials are? Can you see them through the smoke? I have more than one type of potion, are you sure which one you took? What if it was a vial of alchemist frost instead? I think we need to get a high ref to interpret / create some rule on taking stuff from a downed opponent. Also, you might need to make a fort save yourself if you are going to be taking stuff off of someone who's in the smoke.