I'm speculating. But everything seems very suss and convenient for the bloke who survived. The original articles made no mention of anything left behind indicating drug use was a factor. So clearly someone has cleaned house before the 3 bodies were reported to authorities.
Given his friends OD'ed and died, I think it's entirely possible he ODed too, but didn't die, he was nconscious for 24+ . Wakes up as confused as all hell. So it may be as simple as he was inside when the gear hit. They all became comatose at around the same time, his friends outside in the cold die, he's inside and lives. He also may have been more tolerant, given his alleged nickname, 'The Chemist'.
