You always have among the lowest informational posts about methods you don't really understand. Everything is 100% reliable and peaceful with you.
This is stupid, and the only thing likely to come from this method is a flooded bathroom and burns from the dry ice. You also don't appreciate how uncomfortable breathing an atmosphere primarily of CO2 is. To get a basic sense of this, fill a very tall glass a third of the way with a very carbonated soda, stick your nose in, and inhale. Not pleasant, and only a very small fraction of what you describe.