How do you log out hack GU vol 2?

At the very beginning of the game, you can't. The reason for this is that you are in an AIDA mirror server, where all of the players are trapped within the game. After a certain point, you will escape the AIDA server and go back to the real CC Corp server, at which point you will be able to log out. So, just hang in there! You'll be out of there in no time!