hypoxia

If you look at the Wikipedia page on Hypoxia you'll see a picture of a person with Hypoxia in their hand.

His symptoms are typical of hypoxia, and given that he was at 7600ft mild hypoxia seems the most likely explanation of his symptoms.

Why it´s too complicated?: -To kill everybody via hypoxia you don´t need to climb to Flight Level 450 (45k feet).

The hypoxia basically resulted in his brain not being able to discern his imminent death and he wouldn't push the button.

You really can't notice the onset of hypoxia fast enough to fix the problem.

The low pressure outside the body causing rapid de-oxygenation of the blood (hypoxia) is the primary reason for unconsciousness within 14 seconds.

On the other hand, we know that just a few minutes of hypoxia produces irreversible brain damage.

Please check the term on wikipedia, or something: Cerebral hypoxia Damage from lack of oxygen to the brain is well documented and gives different results depending on in which part the damage is.

I would think that the severity of hypoxia depends on where in the body it happens.

Pilots are trained to 'detect' hypoxia but it is still /incredibly/ difficult.

It's tough to switch if you're already unconscious due to hypoxia.

I'm no expert, but I seem to recall that cold limits the damage from hypoxia.

There are plenty of naturally occurring areas of hypoxia, and one could easily imagine an adaptation which allowed better survival in or near these "dead zones" could be quite useful, at least to localized populations.

Hypoxia is another consideration that's worth looking at and would certainly explain the wild altitude changes.

Hypoxia begins to set in as early as 5000 ft, but oxygen isn't even required in aircraft until you spend more than 30 minutes about 12,500 ft.

Hypoxia or smoke inhalation seem plausible.