Do you enjoy tedious micromanagement in an automation game? Well, do I have an expansion pack for you.
This DLC adds a bunch of new buildings that can be manually activated to distract the zombies, which it also adds. Completely at random, some of the people in your prison will become infected with the zombie virus. The game tells you how many, but there is literally no gameplay method of determining which ones. After a while, they turn into zombies, which is equivalent to just having a big fist fight where a lot of people die.
This adds nothing to the puzzle of designing a prison. The game simply kills off a random number of people in your prison every so often and you have to click to hire new ones for staff or literally do nothing for prisoners. It even adds a button you can press to spend some amount of in-game money to have the random number of people who get killed be slightly lower than it would have been.
Distracting the zombies is pointless because the zombies are the people in your prison. If you have zombies in your prison, that means the random number generator has already killed off some of your staff or prisoners completely outside of your control.
Max-sec, super-max, and legendary prisoners already exist within the base game and provide basically the same danger and challenge without the annoyance of being punished even if you do everything correctly. Avoid this DLC.