I just did level 4 again so here is my walkthrough
the the guy screams go back and right along the wall and cheat a little bit, dont over do it, just for a second or two. Then when he makes the sharp turn get really close to his test (because it goes up faster) and cheat the rest of the way, then make a run along the wall to your seat. Dont stop when the teacher walks away from the window he/she cant see you.
and if you still cant do it, the password to get to level 5 is poweroff