O2 locker refills

[Noah Buttes]

i've also noticed that if you refill your tanks from an air canister, not pure o2, and don't ratchet up the pressure massively, you will inexplicably die
it has to be a release pressure of like 80 if you use the accessible high capacity air tanks. spacemen breathe only pure oxygen apparently

That's because the minimum partial pressure of oxygen needed per breath for a human to not start suffering oxy damage is set at 17 kpa. 

The standard air mix is only around 21% percent oxygen. Thus, you'd need to breathe that mix at a pressure of at least 81 kpa to not take oxygen damage.