He says he deserves to be there, it sounds almost as if he is seeking Sanctuary.
One of my many, many theories is that he is Leas ex and the father of Bob, this is the only place he is safe from her.
I don't know if he is seeking Sanctuary
. But then again in the Middle Ages when someone entered Church grounds and claimed it, they also became in effect prisoners because if they left the grounds they were subject to whatever they were seeking Sanctuary from.. At least that is the way I understand it, but there might be more fiction than fact there.
I think it is more a case of someone who has done some really bad stuff and it caught up with him. He understands fully what he did was wrong, and the only way he can atone for it is prison.. Another idea is perhaps he is there because he was evil all his life, did something good at the end, but it wasn't enough to warrant full redemption, so this is sort of a compromise, as in he isn't going to Hell because of what he did, but he doesn't belong in purgatory either.. Kind of like in the Bernard Shaw play, "Joan of Arc." While she was being burned at the stake, she called out for a Cross, the guards and officials refused to get her one, all except for one priest who did go eventually to fetch one for her. Meanwhile a lowly English soldier thought this was wrong and made a Cross out of two of the sticks from the pile they were burning her on and gave it to her, for this act he was allowed one day off from being in Hell, a year..