One might think he was on drugs and really whacked out when watching that piece of video.
One might think he was concussed from being knocked unconscious a few minutes earlier by Chicago Dept of Aviation cops.
I saw that. He was saying "Just kill me" and "I want to go home". He was already bloody, so it was when he ran back on the plane. I am firmly in the camp that believes United was way, way out of line physically removing a paid passenger after boarding, but there was something wrong with this guy way beyond being emotionally distraught from being dragged off the plane. Maybe drugs or psychiatric illness, if this guy was my doctor, I would find a new one immediately.