Weegee Die Hard.

Working in a building in Glasgow today, we saw this odd marking on the ceiling of the lift we were using.
I wondered if perhaps the light fitting behind the translucent ceiling panel had become loose and the heat from the bulb was slowly burning the plastic.....
.....my workmate said that he thought it was more likely to be caused by John Maclean (aka Bruce Willis) having a poo while staking out the terrorists from the lift shaft.
It's not often that I get outdone in the field of childish humour.