Two men are locked in an insane asylum, and one day they decide they don't like that much. So the next night they hatch an escape. On the roof of the asylum there is a small gap to the next roof and after that, freedom! So the first guy jumps over easy and calls the other to do the same; however the second man is deathly afraid of heights and refuses to make the jump. So the first guy reaches into his pockets and pulls out a flash light saying,
"I'll shine the beam across the gap for you! So you can walk across the light and make it!"
The other guy scoffs and says,
"What? You think I'm crazy? You'll just turn the light off when I'm half way across!"