NO they will not let you leave the testing room but for one hour! You are not allowed to leave during your exam either, even if you have to use the bathroom!!!!! Yes they will start the last 2 sections in exactly 1 hour if your not there. Mine ran over 10 minutes and when I got back to the computer, then boom, it was already 10 minutes into the test!!!! Of course you can end your 1 hour early if you want by simply clicking end on the break window!