So the fire alarm wakes you up at 3:00 am. You lie there as it thunders away outside your door. 'It's probably just a false alarm', you think, 'they're always false alarms.' Plus, the bed is pretty comfy. Then you think, 'hmmm, it'd be pretty stupid to die because I was too lazy to heed the really-alarming alarm.'
So, you get up and start walking down the stairs. You live on the twenty-fifth floor, and you breath a microscopic sigh of relief when you pass the twelfth floor, and know that now the firetrucks' ladders can reach you.
The cruelest cut comes when you the alarm stops on the fifth floor. Experience has taught you that the elevators take a long time to reset after a fire alarm. So, the only option is to climb the 20 stories back to your bed.