True, but the stories are good. Undergrad teaching labs were always a bit of a risk. We had one undergrad get the acetone and nitric acid waste containers confused - that one blew up in the middle of the night. Another one was distilling nitric in sulfuric in a Hickman still and thought it would be a good idea to use a boiling stone. Problem was he used a glass bead in a conical vial, the acids superheated, flashed, and blew acid everwhere in the hood. Fortunately it was only a few mL and he didn't get hurt.