Mhmm, I think that cutting somebody's belly open, treating their wounds and making sure they stop bleeding but not doing anything for the wound to close, would make for a nasty psychological torture.
Sure, they might still die from infection, but I think it's worth the risk.
Giving them nothing more than bread with a lot of wood chips, hair and possible needles is a good way to strike fear into typical user of /bant/.
Do make sure to offer this sort of entertainment only as a side dish - semi-starvation like that isn't enough to satisfy somebody, who seeks to strike fear in /bant/ users.
Mhmm.. if you could somehow give them access to various site, such as /r9k/ but with absolutely no knowledge of their wherabouts nor a way to send any video or audio evidence - only pure text and their thoughts - would make for a fantastic show, watch them absolutely wallow in tears once they get banned, that would be fun.
If you can somehow make sure, that the room they are in is extremely humid and never air conditioned - do that.
Only ever let some air in when they literally pass out from asphyxiation. Beware of mock patients though, don't react to any actor-like performance - only ever open the vents once they pass out at least three times and stop moving for an hour.
Some other quick tips..
Constant head trauma is bonkers. Make sure to put some laxatives in his food as well. If they are epileptic, do something funny with it - maybe force them to sleep with their eyes covered with hands. In fact, do that to everybody, epileptic or not. Flick on and off the light like crazy and 24/7.