Good thinking, but executionally weak.
Buggy, as was mentioned: I also had the "no penalty for hitting a pac-man" error, and in addition I (4x) got into a mode where all of the characters' positions on the screen wouldn't change but apparently were still moving programmatically (I would die shortly after). I think that this bug was prompted by hitting a left or right arrow while in an up-down corridor, but that may not have always been the case.