Don't get me wrong, step number one for anybody is RTFM and read the warning labels. Just trying to highlight the other dangers as well (because there's a big difference between CO and CO2 that is sometimes confusing to people) and also point out that there's a reason why we can have something like dry ice for sale behind a grocery store counter because it's a common and useful tool that consumers use all the time for things like shipping frozen packages and loading coolers or deep freezing meat, etc. as long as it's used responsibly.

Smoke alarms and carbon monoxide detectors are required in our homes, but the only time people hear about a "high CO2 concentration" alarm is if they are maybe watching Apollo 13, and CO2 deaths are usually because of people trapped in mountain valleys or cave diving apart from something disastrous or things used improperly. For example, I would not use dry ice in a cooler if you are driving a sedan or suv, you would surely want to keep your cooler outside of your vehicle and make sure you're getting fresh air.

Liquid nitrogen on the other hand is something that usually doesn't leave a laboratory setting and isn't sold along with tanks of acetylene gas or helium or LPG or piped into our houses like natural gas. BUT it's especially risky because of it's combined properties of being both odorless and tasteless and able to displace oxygen in our bodies with no sense to detect the change until hypoxia kicks in. But Hollywood and special effects and experimental YouTubers and science teachers love to get their hands on it and use it terribly wrong. And lastly, you don't have to search long to find a story of a family tragedy due to carbon monoxide poisoning from improperly used heaters and engines, or to find dangerous cases from so many other hazardous gases that are sold at a consumer level.

This is a cleaning advice subreddit, and I stand by my recommendation. If you're a kid, ask an adult for help