I bet it’s implemented in a way that is not safe based of those hoses and his breathing pattern on the exhale. I’m sure he’s getting far too much of a dose and I guarantee the system doesn’t flow properly so that new fresh is being introduced. I bet he lost 30 IQ by the time he was let out. Won’t be permanent damage unless he had a bad reaction to poppers. By the next day he’d feel fine
Just make sure the hoses are short and that he can actually get fresh air and not recycling the carbon dioxide that would build up in a hose longer than about 12 inches.