lol i am aware that if you throw somebody down to 100 feet real fucking fast, people will universally get narced.
the point was that there's no formula like for alcohol intake or other forms of intoxication where you can reliably estimate based on body mass + metabolism how much it'll take for a specific person to be affected. you take someone down to 60 feet and it's unpredictable whether they're good or not at that depth. the big 250 lb guy may completely lose his cool while the petite 120 lb woman is completely fine. we don't have clear science on why. people's personal limits of going from the testing threshold down lower aren't understood, the body chemistry of it and the way that nitrogen acts on different people's biology hasn't been deeply explored due to obvious limitations.
also from the 2nd paragraph of the wikipedia page:
Divers can learn to cope with some of the effects of narcosis, but it is impossible to develop a tolerance. Narcosis can affect all divers, although susceptibility varies widely among individuals and from dive to dive.
bottom line, some people are weirdly tolerant of deep dives while it hits others like a train. but the above paragraphs and in-depth explanation kind of break up the flow of the story. sorry if the original post got misconstrued without my extra rambling.