I just had the unfortunate experience of dropping my Still in the Muufo Bureaucratic Hall while I waited, then exiting and reentering without stopping to pick it up again. phelps.mike said that because locations like the Hall are instanced, they are closed and emptied when the player leaves. Indeed, it looks like my full Still is gone for good; not in my inventory, not on the street outside.
For locations like this, I propose that the game warn players if they've dropped something and haven't picked it back up before they leave. Either a warning, or just an automatic pick-up on exiting instanced locations.
It would also be nice to get my full Still back, but I won't hold any expectation of that. It's not TS's responsibility to do stuff like that. :)