You all want to be a professional of some sort some day, so the time to begin is now.
Every instructor has certain expectations regarding acceptable and unacceptable classroom behavior.
To help foster a positive classroom climate, I've listed a few of the more important ones for my classes. This list is by no means meant to insult your intelligence, as I am sure you already practice these professional behaviors in your life. Rather, it is simply a means to formalize what I expect so you know ahead of time. I'd strongly prefer that you did not leave the room once you've started taking an exam. Of course, not showing up will hurt your grade.