Maybe you can lighten the load a little. Let some of the stuff out. The vats aren’t in use, but on the other hand, you don’t know for sure that they’ll check them in the morning, or whenever this place opens up again.
Well, you might be able to find a jar or something so you can take the excess yourself. You pry open the barrel and quickly look around.
Aha! An empty bottle. Better for pouring out of than into, but there’s a scoop next to it, which will probably help. Arsenic’s a powder, isn’t it? That’s what you remember from the plays where it was used as a poison. So this should be good for transferring it quickly.
Except, when you actually take the time to look in the barrel, you don’t see a powder. It takes you a moment to realize what you’re seeing.