Stupidity: Lecter fires the first bullet to alert the police that something is up, and the lift goes up, then comes down. Now in all this, only 6 or 7 go up the floor where Lecter was. Why aren't police sent in groups to investigate every floor? Lecter could have been anywhere, instead there are about 30 police huddled on the lobby floor.
Stupidity: The crack house workers are all topless to prevent 'hiding' any product for personal use. Yet are also wearing parachute type pants that they could easily hide things in.
Stupidity: Just after Ricky has beaten up Tarzan, the warden has the ceiling of the cell Ricky is trapped in lowered in an attempt to crush him. However, earlier in the scene, Tarzan made a huge hole in the wall of the cell to get into it. The hole in the wall is even visible in the background when the ceiling begins to lower. Ricky could have simply run out of the hole in the wall to get out, rather than try to hold the ceiling up with his bare hands. (01:02:48)
Stupidity: When Laura goes back to the house to get her bag, she takes off her wedding ring and flushes it. Problem is, she knows how her husband is and doesn't take the time to make sure the ring goes down! But she makes sure there's no other trace of her being there (flushing her hair down the toilet and drying the floor off from her wet feet!).
Stupidity: Given Louise's character, it makes no sense at all for her to leave Thelma in charge of the money. She's known Thelma for years, and knows fully well how flaky Thelma is. And Louise is shown as a person who lives by "If you want something right, you've gotta do it yourself". She's responsible, perhaps even uptight, at that point in the movie. So it defies everything about her character that she would let Thelma guard the money - it smells like a device set up just to allow the money to be stolen.
Stupidity: The Foot Clan knows that April O'Neil is an ally of the Teenage Mutant Ninja Turtles. Since the Foot Clan hasn't been able to find the Teenage Mutant Ninja Turtles for where they live a easy solution would be for them to go to April and ask where are the Teenage Mutant Ninja Turtles. An explanation is never given in the movie for why the Foot Clan never use that easy solution.
Suggested correction: First of all, the Foot Clan at the beginning of the movie is disorganized. Secondly, upon Shredder's return, he plants a Foot soldier named Freddy into April's news crew in order to keep an eye on her and find out where the Turtles are. Then they change tactics when they discover there is still some of the mutagenic ooze around, which they then decide to use to create their own mutants to lure the Turtles out of hiding.