I saw very similar stuff like this on occasion, when I was a Correctional Officer. The first few times make you feel VERY ill but, sadly; you get used to it.
I saw an inmate get his head taken off--piece-by-piece--when another iinmate decided to put some Jack Mac (canned Mackerel) in a pillowcase and use it as bash the other guy's head into many pieces.
When this kind of thing happens--we are NOT allowed into the area (for employee safety) in case it is also a ruse just so an inmate can make a name for himself and kill an officer.