It's virtual reality. [They did kind of just wing that on him...]
For example, some inmates have had collars put on them that bans any physical touch. A simulated reality could enable them to have physical intimacy-- not even sex so much as hand holding, or an embrace, with someone else. And then there's the gaming aspect, I bet it wouldn't be hard to rig up a few game simulations... [Like zombies...]
In the works there are ideas of rigging up areas not in the dome to explore, or relax in. Visit home, in a way. Or at the very least, memories of home...