Punch him in the face
You bring your hand back then swing it forth hoping to hit Dr. Gero in the face. But he catches
your hand in his fist. So you swing your other hand at him. But he catches that one
too with his other fist. Then you try too kick him and head butt him. But he is so strong he squeezes your hands and says "Say Uncle". When you don't, he swings you up in the air as strong as he can, then finishes you off with a ki blast.