Working in a prison is like going through a meat grinder. You come out at the end of a shift with your head feeling completely mashed. One of the first incidents I remember is a prisoner sitting in his cell cutting his arm because he wanted me to get him a cigarette. He knew exactly what to do without putting his life at risk.
Things in prisons have changed a lot since then. Prisoners are much bigger than they were 30 years ago due to use of steroids inside. And they are more likely to be in gangs.