I'm planning to wet the floor in the grocer to create the spill.
Why would you want to wet the floor in the store?
So I can pretend to fall and get them in trouble.
Creating a mess on purpose is wrong. You should help keep the store clean. Others could slip on it and hurt themselvs.
I want to record it and put it on YouTube!
You are going to get the store in trouble. You shouldn't create situations on purpose for entertainment, as people can get hurt.