Cause: not holding the left/right directional key for long enough. (IE less than a frame after entering a teleporter) This causes igor to appear in the middle of the teleporter, and if you hold one direction key, you go in that direction.
_
1____..___...__..__
__..__..___...__..__
__________..______
.......______|______
...|_______......___1
.....__________|
(Yay for crappy ASCII of levels!)
Key:
. = empty space
_ = floor
1 = teleporter.
At the bottom 1 if you hit it and release right the moment you touch the teleporter, you can press left and hit the wall, and because MT put a bit of codeing in that stops igor from teleporting unless he has completly emerged from the teleporter, you can't teleport untill you go out of it.
(What the heck... WHY did I pick this up? XD At least I'd gotten over 10 Silver Mushrooms first.)
(Thus I only lost one life, to the fireball.) 
quest! also completed armaggedon
, and a good score. The fireball got me at level 96
!
?
? :p