Stupidity: When Donatello frees the professor, he gets his head in his visual range, and same goes for his thick inhuman hands, but he notices only when the plot says so, a few moments later. (00:52:50)
Suggested correction: The professor is in noticeable distress, likely from having been tied up for so long and hearing the fight between the foot soldiers and the turtles occurring just outside, so he isn't paying much attention to who is rescuing him at first; he just wants his hands untied and to get the tape off his mouth.
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)