Being a Ref in Mixed martial arts is without a doubt a tough job.
We've seen many incidents before in all combat sports of a ref getting 'touched' by fighters and that's a great punishment, up to prison.
Lately, this past week during a German promotion "Aggrelin's 19th card" exactly in the main event between Nihad Nasufovic and Wilhelm Ott.
Ott was caught by a hard rear naked choke, the referee simply watched him tapping out and didn't step in immediately to stop the fight.
Then things got crazy, obviously the fight stopped late the thing that made Ott pissed and he went directly to the ref and punched him to the face.