I think the main problem I can see with that design is that you are using the road door as your main entrance, I can easily see a prisoner making a break for it through such a slow closing door when it's used so often. Personally I prefer an airlock in the main entrance, a short corridor with 2 jail doors at each end and a permanent guard posted in between.

I would personally like to voice my hatred of the inmate nutrition research grant, I lost 10 inmates and 3 guards during the food shortage phase before I gave it up and I cant cancel it so it's stuck there on my list taunting me.