In most U.S. jurisdictions violent inmates are locked down most of the day. Most medium security inmates don't want to spend an extra minute in the pen if they can help it and act accordingly. I worked in medium security prisons in Tennessee and Colorado as a counselor. After a while it's like babysitting for a bunch of loud kids.
Bless you for doing that work, but all in all still good you can say it in the past tense. :-)