The first time I took the exam (took it 2nd time this fall and passed thank you Lawdy!), they had already shut the doors to start handing out materials and give instructions. You all know that once that happens they don't let people leave their seats. Anyway I was sitting near the back of a room of probably 350 people, and right in the middle of passing out materials some guy at the very front stands up, face white as a ghost, turns and makes a b-line for the exit, as he's walking down the middle aisle he is saying "I'm sorry! I can't do this! I'm sorry!" in a defeated voice. He actually breached security at the doors because I'm sure the proctors had never seen anything like that before. Safe to say much of the room was thrown off! A few of the proctors chased him down in the lobby and I could hear them coaching him up to come back in and take the exam (he had to stay in there anyway at least until the exam officially began). Sure enough he came back in and took the test! I wonder how he ended up doing? I hope he passed, that would be a legendary story if so.
Armed with hindsight, for how unprepared I was when I took it the first time, I might have gotten up and done the same thing!