When I worked at McDonalds in the late 90s (literally 1999) I ended up the morning delivery manager.
I had close to fuck all training beyond counting boxes and putting them away. So when the driver asked if I needed my cola topping up I said yes. It was on the list that I needed 9 boxes after all.
What wasnt told to me was that we had a tank of the pre mix syrup that the machines defaulted to in between the bag in box emptying.
The driver hooked up a hose to that, unknown to us, full tank. 20 minutes later we went into that room, having finished putting away the delivery. Cola syrup was coating every surface of the room, it was easily 2 inches deep on the floor.
I spent about 3 hours cleaning that room, even having to mop the ceiling.
Afterwards I was sent home as it had dripped on me and I was just coated. I didnt have a shower, so i had to take 4 baths before the water stopped being still coke.