To risk fuel starvation because of an abnormal condition
Intruder - Don't you heavy iron guys carry fuel for pressurization failure ie transit at 10,000 to an alternate from any point along track?
My reading of FAR 121.329 and 121.333 prompts me to agree with the interviewees (R2000/1830) answer. Procceed at 10,000. 121.333(b) in particular I think is most relevent.
"Crewmembers. When operating at flight altitudes above 10,000 feet, the certificate holder shall supply enough oxygen to comply with §121.329, but not less than a two-hour supply for each flight crewmember on flight deck duty. The required two hours supply is that quantity of oxygen necessary for a constant rate of descent from the airplane's maximum certificated operating altitude to 10,000 feet in ten minutes and followed by 110 minutes at 10,000 feet. The oxygen required in the event of cabin pressurization failure by §121.337 may be included in determining the supply required for flight crewmembers on flight deck duty."
That is, no oxygen, no above 10,000. (As I read it. Stand to be corrected)
R2000/1830 - Stick to the radials rather than them whining turbines. (Money aside)