Also the inmates have basically an unlimited amount of time to think things over. They have all the time in the world to go back over past events and plan for t

Also the inmates have basically an unlimited amount of time to think things over. They have all the time in the world to go back over past events and plan for the future interactions. The guard may not think twice about a particular conversation while the inmate may spend the next 24 hours going over it in their head and figuring out an angle. If they're not switched on and maybe a bit paranoid the guard may not realize that what they think is a conversation is actually a science experiment with them as the subject. Working with people who can spend every waking moment figuring out how to get into your head could be frightening.