He does say at the end, "However, if you are sensible, keep your head low and steer clear of drugs, debt, stealing from other cons and ‘grassing’ (informing on fellow prisoners), you are unlikely to be the target of any violence."
Also following the unwritten rules esp the newer gigantic dorm prisons where there are countless rules since you're all crammed in there. The violence here is from your own group if you break the rules because they're trying to get rid of you from that dorm before it escalates. A typical prison intake you are met by another inmate who already somehow knows everything about you and has already announced you to everybody else. He brings you to your group in the dorm and they tell you the rules. Nothing ever happens after that for 90% of inmates not involved in gangs except really grinding prison labor everyday.
