RE: TIL The Vending Machine Was Invented By Heron of Alexandria

This is fascinating and I hope this really is the earliest known coin operated vending machine and that Heron did invent it. But what I can't work out from the video demonstration of how the machine functioned is that when the coin is dropped into the slot the weight of the coin hits a lever which releases some water, but surely the coin would slide off the lever instantly and so the valve would have such little time to release a sufficient amount of water?