The peak of Mount Everest is 8,850 meters (29,035 feet) above sea level. No other mountain on Earth has a higher altitude
And people go there without supplemental O2 all the time
But it takes longer than 30 seconds to climb.!!
Many days of slowly ascending allows your body to get acclamated. Plus being in good physical condition.
None of which applies to 99.99 % of a few hundred passengers