Now with v1.0, you can play escape mode, which is exactly this, with the exception of being able to escape, fight, and build up your stats. You have to go into the menu and then choose which prison you want to escape from, you can escape from your own built prison, or you can go onto the steam workshop and choose a prison from there.
Also, if you want to become a criminal due to being charged with "Criminal Negligence", you'd have to obtain 20 deaths in your prison, then the warden calls you and gives you a warning, if you obtain 5 more deaths that day, you're done, you lose control of the prison and you're now a prisoner.
If you want an easy way to do this, you can setup a yard surrounded by fences, have ONE opening and leave it insecure (so they'll try to run out), but when they do, have an armed guard there and have free fire enabled, that'll get you fired fairly easily.