The Maniac thought he was successful in fighting off whoever was attacking him when he noticed they were no longer attacking him. The Maniac got up, still ready to toss his fists, legs, and various other body parts in whatever direction should someone go for another assault.
The Maniac was surprised to get to his feet without being hit. Next thing he knew, though, another body had run into him. The Maniac was then forced back and ran into the crate, causing him to yell out and lose control of his legs. If let go, the Maniac would fall forward, otherwise, he was just kind of in Boxer's grasp.