i met up with someone, we agreed to try to go out to the surface through one of those holes to the o

i met up with someone, we agreed to try to go out to the surface through one of those holes to the outside. my friend stepped out first, and immediately they started stumbling in shock. they seemed to be in a lot of pain. they vomited a bunch, then collapsed and stopped breathing soon after. their skin started blistering too, especially around the head and neck. something is preventing us from leaving. im scared.