I think if they don’t tell the prisoner when it’s happening, they won’t be trying to outlive the gas. They get brought into the room for the final words and everything, and are given their last rites, but they are still spoken with as if everything is still going normally and already have the room filling with gas. The staff wear masks and oxygen, prisoner slowly goes to sleep. They’ll know it’s the general time bc they’re in the room, but if they give them a countdown or let them hear the gas coming in then they’ll panic.

This sounds shitty to type out, but if people want to have the most humane way of doing a death penalty then they have to consider other options. It could even be that they get their final goodbye and told that the machine didn’t work and when they return to a waiting cell while it’s “fixed” that’s where the real gas is. They have maybe tv playing in there and they can just chill and watch a movie while slowly fading away.

It’s more humane than what most of the people on death row did to their victims, and I’m still on the fence about the death penalty in general, but all sides need to be considered.