The reason Wolfoo could not switch the robot off is that this robot did not need battery or electricity to run. He was run by hatred towards humans. The robot wanted to attack Wolfoo and he fighted against thanks to the part of Slime’s body.
However, the robot still could use his laser to attack around. This made the special machine that kept the robot’s lackeys broken and they were going to be destroyed but Kat and the other friends tried to save them. The lackeys after that realized that humans might be as bad as they thought and they did not follow the dictator anymore. They also wanted him to let Wolfoo go when the dictator caught him and tried to kill him. Unfortunately, Kat turned into wood completely.
The dictator thought he could not defeat Wolfoo and his friends so he decided to destroy the door that led to the human world. Wolfoo tried to stop him and both of them fell into it.