When a fire alarm goes off in the middle of the night, and you're trying to get your shoes on while standing in front of the box that emits that horribly loud and annoying pitch, don't attempt to block the noise out by holding your hand up between you and the box. It won't work.
While people are milling about outside the building during the fire alarm, random people are looking at the board of warning lights in the foyer, pointing to the lone flashing bulb:
"Looks like the junior fire patrol is hot on the case.
They have identified the cause of the problem as being that flashing light" - me
I later discovered that the flashing light said "Fire Alarm Trouble". Great. No Shit.