out like the vapors
Leaving a place relatively quickly.
When Louie's beer shits started acting up in the middle of math class, he realized he'd better be out like the vapors to save himself from the biggest embarrassment of his life.

"I don't wanna rape ya, I just want the paper
The Visa, capisce?  I'm out like the vapors."
-Notorious B.I.G., "Dead Wrong"