My only concern is what could actually be done with this idea. It seems kind of like an excuse for disposable, consequence-free vore. By making all of the potential victims the absolute worst of the worst there is no reason to actually root for them, or to give their potential deaths any real weight.
Also, in terms of building a prison (assuming they could put it anywhere via inter-dimensional travel) why not just stick it on, like, an airless, molten moon or something? The location and the way the Warden has interacted with the local preds seems like it was done to make a point.
A much more interesting way to handle this idea would be if those incarcerated within the prison were not actually criminals. Rather, they would be political dissidents, POW's, undesirable ethnic/religious groups, and so on. People who haven't actually done anything wrong but are being shunted off to a death-world prison by a repressive regime/occupying force. This would actually give us a reason to, well, care about this idea at all, and to root for the escapees. Without a reason to care it's just... kind of a thing where people who arguably deserve to die get eaten every now and then. Pretty boring all around.