A man comes into the ER yelling, "My wife's going to have her
baby in the cab!"
The ER physician, desperate to help the lady, grabs his stuff, rushes out to the cab, lifts the lady's dress, and just finishes jerking off her underwear when he looks at the lady's shocked face.
The physician then realizes his blunder and turns pink with embarrassment -
There were several cabs lined up and obviously he was in the wrong one!