> The autopsy shows that Schoenig died from asphyxiation
Something doesn't add up. When you pass out from holding your breath, you automatically start breathing again. What must have happened is there was so much nitrous being used, and not enough ventilation, and the nitrous displaced the air on the floor. So he passed out, fell down, and when he would have started breathing again normally, there was no air on the floor to breathe. No one thought to open a door to let the nitrous escape, so the CPR was in vain if there was no air to get into his lungs. Then his friends cleaned up all the empty whippets before the police arrived, and got their story straight: "he did one whippet, and just died," when there was probably hundreds of whippets being released in an enclosed space, pushing the air off the floor and creating a zone of asphyxiation.
So I suspect this is precisely what I described in my post, asphyxiation from displaced air on the floor. The nitrous itself did not hurt him, it just made him pass out because there was no oxygen in his lungs when he was holding in the nitrous. What killed him was asphyxiation, not toxicity to nitrous.
Decades ago, 2 kids died this way in a pickup truck. They even had the windows open, but the nitrous displaced the air along the floor, they passed out and folded over, with heads below the door-windows, and asphyxiated. More recently but still years ago, a high school boy and girl died together the same way crawling under a large advertising helium balloon to hear their voices sound funny... but there was no air under there, so they asphyxiated. The helium itself did not kill them, it is inert. The lack of air causes asphyxiation, and that is what it is fatal.
So, again, nitrous itself will not hurt you, has never hurt anyone ever, but because it is heavier than air, it displaces the air, and in an enclosed space it will push out all the air, and death by asphyxiation occurs.