TMNT Season 4 Episode 19 - Insane in the Membrane Episode Title:Insane in the Membrane.Episode Description:The mutant outbreak continues to spread throughout the sewers and subway tunnels while the Turtles try to contain the threat. Back at Area 51, Baxter Stockman prepares a new body for cerebral transfer despite warnings from Agent Bishop. When Stockman's body begins to show signs of rejection, he becomes delirious, which leads to a rampage against the person he believes to have caused all his problems, April O'Neil. In the end, seeing April as his mother due to his delusions, Stockman sacrifices himself by being drowned in the East River while handing her to the Turtles and Casey.