This is where the family of a murder victim would sit to witness the execution of the person charged with the murder and await closure (I guess). Since the executed were convicted criminals, the response in the tour group to visiting the gas chamber was gallows humor instead of, say, the vague unease of knowing this was where the state-sanctioned killing of human beings took place, or wondering aloud how many people put to death on the other side of the glass may not have actually committed the crime for which they were charged.
(While visiting the prison, I was careful to avoid eye contact with a certain kind of visitor, lest they get the idea that I wanted to hear their opinion, which is almost always ignorant, reactionary and racist. In a way, I did us both a favor. I'm sure they would've been equally disgusted with my pinko opinions.)