Fully depressurising an aircraft whilst staying level for even a short period brings other problems. Not least the inability to breathe easily, ( look up pressure breathing, time of consciousness etc), see, function and the fact that you’re probably in your shirt sleeves at -58.
A dive to flight level 250 is a decent compromise whilst maintaining maximum forward Mach no. It’s also a good flight level when you get there for maximising true air speed as you turn towards your alternate; probably Shemya on a dark cruddy night lying some 1200 miles distant. And it’s manageable from the point of view of discomfort and o2 depletion.
The checklist makes the best out of a bad scenario; I can’t think of any case where this has happened where the poor unfortunates were able to survive. Happy to be proven wrong.
One of the many joys of hauling rubber dog 💩 around ( in fact that would be infinitely safer) whilst carriers try to maximize yield by transporting ever increasing amounts of this stuff.
https://www.aerotime.aero/27655-Hong...ort-fire?v=amp
And that was a relatively small load.