Stupidity: The Foot Clan found the Turtles' hideout in the sewers thanks to one of their members who followed Raphael when he was carrying an unconscious April O'Neil after he saved her from the evil ninjas. When Shredder later is trying to find the Turtles, it takes Danny's betrayal to point him towards April. How stupid does he have to be? It's a connection anyone would have made, it was the second time she was saved, even.
Teenage Mutant Ninja Turtles (1990)
2 stupidities
Directed by: Steve Barron
Starring: Sam Rockwell, Elias Koteas, Judith Hoag, Josh Pais, Michelan Sisti, David Forman
Other mistake: In the music within the ending credits, the lyrics incorrectly state that Raph is the leader of the group when all Turtle fans past and present know it is Leo.
Casey Jones: This is great. First it was The Farm That Time Forgot and now this. Why don't I ever fall in with people who own condos? Probably hard to get good maid service in a sewer. Maybe you guys should try Roto Rooter, huh?
More trivia for Teenage Mutant Ninja TurtlesMore questions & answers from Teenage Mutant Ninja Turtles
Answer: Most likely to kill Shredder and make sure that there would be no way to come back but, as seen in the sequel, Shredder does return.