Carbon DiOxide is NOT poison, it is a harmless, inert gas.
As long as you have Oxygen, you will be fine.
Carbon Monoxide? That is an entirely different story!
Look it up
Check out movie “Apollo 13.” Astronauts had to literally fit square pegs into round holes to prevent death from CO2 poisoning before any of the many other threats could have killed them. There also were hundreds of folks who died of CO2 poisoning in Africa when when a volcanic lake suddenly released a lot of it. CO2 is certainly not the cause of climate change (it may be an effect of it from other causes) and isn’t poisonous at common levels, but too much, or even too little of it, is dangerous. Even too much water or O2 can kill you.
I imagine that is the effect of the CO2 - displacing the oxygen. Perhaps like the hallucinations that sometimes occur with climbers at VERY high altitudes and under extreme body stress.
I knew a gal that claimed the university was doing experiments on her through radio waves. I just figured it was because she was a diagnosed paranoid schizophrenic, but now....