I'm aware that N2 leads to a quick and painless death; I've been warned more than once by lab-workers of the dangers of opening liquid N2 tanks in basements, ev

I'm aware that N2 leads to a quick and painless death; I've been warned more than once by lab-workers of the dangers of opening liquid N2 tanks in basements, even though I've never been near a lab. But I thought there was some downside? I can't remember. Obviously, it's difficult to dose accurately, and it's impossible to stop dosing once you've had enough. So there is a risk you'll be discovered in a space filled with an odourless, invisible toxic gas. What does a scuba mask do, that you can't do without a scuba mask? Surely, if you can breathe in and out, you can exhale CO2? My understanding is if you breathe N2, you first become unconscious (with no preceding wooziness), then you die. So there's a huge risk of accidents. Maybe that's why I thought there was a downside. At any rate, "being discovered" is something I'd want to avoid at all costs! I can't imagine what it would be like to discover the body of someone that had killed themself.