Prison is like training camp for these types. Plenty of time to lift some weights, make some connections, get some fresh ink, possibly test one's skills in a fight, get some nutritious food and a little bit of rest on a (relatively) nice bed, maybe see a doctor if they need to, and so on. After seven months the government has a much more dangerous criminal than they did before.
I'm all for seeing him swinging at the end of a hemp rope after a short fall. Cheaper and more effective than running pre-season mini-camps for professional violent criminals.