I've only seen a few rare cases, like this one, where people were susceptible to definite AMS problems doing this. It is pretty clear for these few that their "intermediate height" for a first night is somewhere below 10k.
Steve , we are both correct. Most people get away with it, but a few are very susceptible. Unfortunately there is no good sea level test to predict this, only experience up high. First time, or even subsequent ones , can be hard. If they gave him O2, I wonder if if had more than AMS, but also HAPE.
AMS usually starts to get better once the decision to descend has been made or with only short descent. Generally speaking, HAPE and / or true exhaustion and/ or other illness would take longer.
A bit smokey in Mammoth.
