You and Red had to figure out how to try and tame Mewtwo. Mewtwo was going on a riot in the caves, and it would be bad if they got out. But the thing is, you and Red knew that one of you would have to sacrifice your life to calm down Mewtwo. It was most likely not gonna be a Pokemon Battle against Mewtwo. No, they would try to kill you the moment you're in their sight. Now you two had to figure out who was gonna go in and possibly die just to save Kanto, if not the whole world too.