"Job Interview" joke

4 guys go to this job interview. They all pass a test, and have one final verbal question from the employer. They all file in in front of him.
"Ok," said the employer, "I have to ask you one more question, and this decides if you start working for me."
He goes up to this first guy and asks, "What is the fastest thing in the world?"
The guy looks at him, and goes, "A thought. I mean, it just appears in your head."
"OK... " the boss goes.
He walks up to the nexy guy.
"What is the fastest thing in the world?"
"Ummm... a blink of an eye. It is just like, you dont even notice you blink at all."
"Ok..., " he says as he walked up to the third guy, "and you?"
This guy answers right away, "Turning on the light. I mean, you just flick it on and it is there."
"Alright." He walks up to the last guy.
"You know the question... "
This guy takes a couple of minutes to think. Finally, he says, "Diarrhea."
"Please explain," the employer says with a puzzled look.
"OK, the other night, I was laying in bed and my guts were just hurting. So i got up to go to the bathroom. I got to the door, and before I could think, blink, or turn on a light, I shit myself."