Quote from Emptyeye:
TMNT: 39M 9S. At this point, I'm convinced the game is just having Shredder mutagen gun me out of spite. Had him in the left corner, was whacking him with Don..and I get mutagen gunned out of nowhere. >_< I posted "I'd like to throw [This game] through a window" on The Shizz.
The fastest way to take out Shredder is clearly to corner him. However, since there is a safe spot on the right platform, it might be worth sacrificing a couple of seconds and go with that alternative instead. If you only have one shot, as in this case (I don't know how you're supposed to beat Shredder with any of the other turtles than Don), it sounds like risk is just being added. I'm sure you're already aware of this, but it was just a thought.