Let us say that for arguement's sake that he aircraft depressurises between Urumqi and Kashi . He physically cannot make it back to the cockpit without the need for supplemental O-two.
Whilst ageeing 110% that the 777's so-far-aft-it's-halfway-forrard-again pilot "rest" area is a total joke, any captain who takes his rest over that particular sector, with an LSA of 28,000', is possessed of a lot more
sang froid than I ever will have - or alternatively, a lot less imagination that I already have.
Hands up anyone who has made it back to the cockpit after his "rest" even ONCE without having to negotiate his way past a trolley blocking both aisles? I don't even want to imagine what it would be like getting past 300+ panicking Indians
(let's tell it like it is - whatever EK route you're on, 95% of the pax will be Indians), if one day I might have to get back to the cockpit after some sort of incident, especially if it is something like a cabin or toilet fire.