Stories from the Lab

This story doesn't actually come from my lab - it was done in another lab within the department. Someone made a piece of metal touch a plug that was half hanging out of the wall...nearly blew their lab up. Luckily someone who knew their stuff managed to stop it before the sparks lit something. Here's the photographic evidence of what's left of the plug.
I'll leave this clue....zui hao pengyou!