[Sorcerer Gas Destruction] Deoxygenation is seriously off

[MisterK]

Deoxygenation spells reduce the amount of oxygen in the area of effect. The Note 3 below the list spell descriptions indicates that
"When the oxygen in an area of effect falls below 50% of
normal, anyone in the area of effect must make a RR (attack
level is 1) or fall asleep (this RR is modified by -2 for every 1%
under 50%). Of course, if the % drops below 10%, suffocation
becomes a danger. All fire spells in an area of low oxygen are
modified by -2 (or -2 % effectiveness for non-attack spells) for
every 1% under 50% of normal oxygen."

This is slightly misleading, and quite wrong. The medical effects of deoxygenation at less than 10% oxygen in air (50% of normal, which is 21%) are "Inability to move. Fainting almost immediate. Loss of consciousness. Convulsions. Death."
Sleep is never a possible effect of reduced oxygen levels in breathed air, except as a side effect of fainting. The first noticeable effects (reduced coordination, reduced physical and intellectual performance, etc) appear as soon as 90% of normal, major cognitive effects appear at around 75% of normal, physical impairment with fainting and vomiting and possible permanent side effects appear at 55-60%.

In other words, deoxygenation is not a soft way of putting people with low resistance to sleep slowly. It is a very sneaky way of killing people slowly at level 4 (need 50 rounds to reach the lethal threshold), and not-so-slowly starting at level 12 (need 10 rounds). Since cognitive functions are affected quickly, people affected may not even notice it and actually feel well (if somewhat light-headed) until they start vomiting or losing consciousness.

I don't think RRs would work the same way here - people making their RR would be able to hold out longer but would still suffer the effects, especially inability to think straight. I think making the RR should allow one to notice that something is not right in their (or other people's) behaviour. Failing RR would mean that it goes unnoticed.

Additionally, I would give actual resistance (in that the effect is lessened) for people born and raised at high altitude levels - oxygen levels naturally decrease with altitude (at least in the troposphere), so people raised at high altitude would have a natural resistance to the early phases of that spell, and the danger threshold would be pushed back.