I wasn't on shift when it happened, but A restaurant I worked in *many* years back had an "ice in the deep fryer accident".

A cook was dumping fries into the fryer (instead of into the basket, like you are supposed to do) and saw a fist sized chunk of ice go in.

Luckily for him fryer fryers were at the end of the wall between the fry/grill area and the rest of the kitchen So he just ducked thru the door before things went "Whoomp!"

Fortunately there wasn't a fryer, but they had to close the restarant not only clean it up that night, but have it closed for more cleaning the next day.