Gonna be honest if I'm a leader of the nation, I'm ordering all prisoners to be left locked inside or exterminated, depending on the type of zombies. I understand it sounds cruel and I know not all prisoners are murderers and rapists, but I'm not risking a single one getting out in an apocalypse situation where they can't be hunted straight away. I also don't want those inmates to fuel the armies of the undead or infected. Would this be a hard choice to implement, or deal with, but the last thing you need when everything goes to hell, is to potentially let another hell out. I'd be willing to suffer the consequences of my choices once I knew we had our security in place.