In the original Ninja Turtle movie and still the best, Shredder almost met his end by falling off a building, well, Splinter pissed him off enough to be enraged so he would do something incredibly stupid, he did exactly what he did tried to make the ninja turtles do, lose their cool which would make it easier to win.
So Splinter tricked Shredder then tried to give him a motivational speech while he hung for dear life off the top of an apartment building, definitely not the time to give a speech but hey, that's master Splinter for you.
So Shredder falls after trying to assassinate the rat that held him over the building and in he goes a hundred or more so feet into a garbage truck, knocking himself out and most likely barely breathing.
In comes renegade Casey Jones who pushes the lever down to squish Shredder, a human being who is clinging onto life, who is in most likely a coma, but Jones takes it upon himself to straight up murder him.
You would think after Shredder woke up and returned to his Foot clan that was now in shambles because Leonardo killed half the teens in the first movie, that he his first priority is to find the stupid hockey mask wearing dude that tried to kill him, but hes more pissed at the ninja turtles, why?
Casey Jones should of been assassinated in the second movie! At the very least attempt to get Splinter out of hiding so he could feed him rat poison. Splinter and Casey should of been number one and two on his hit list, since he basically kicked the shit out of the turtles, I mean Leonardo did the most damage but still coildnt completely get the job done.
So there you have it....Shredder should of thrown Casey Jones off the Empire state Building onto a billion legos.