I once spent seven months, twenty days in a hermetic underground maximum security facility. There was zero physical contact with the outside world and material items were tightly controlled. Toothbrushes were cut off to a length of 2 1/2", no pens, paper clips, staples, etc. Even Q-tips were prohibited. Pencils were 2 1/2" stubs. Safety razors had to be checked out. It was a very hard place to do time.

Inmates still stabbed and bludgeoned and choked each other and staff. They would end up naked in a cell with no bedding and three plexiglas walls, under constant surveillance, but evidently it was worth it to carry out their assaults.

If a person doesn't care what happens to him as a result of his actions, and he is committed to an assault, it's very difficult to prevent him from carrying it out.