There is an added level of weirdness here, given what “zizi” means in French.

You might have touched on something here. Perhaps it was some sort of extreme performance art that he wasn't going to go through with, but found himself in front of an appreciative audience and thought, ah, let's live a little.

It just wouldn’t have been the same if he had done it in Pizza Express.

Maybe then his project would have been to try to express a pizza. Lucky for the diners it was Zizzi's, then.