some older planes have regular oxygen tanks which, depending on passenger load, can last quite awhile.
I agree that the plane in this case should maintain an altitude consistent with MEA/MORA and low enough that you won't need oxygen if the event happens again.
isn't it interesting that newer planes have less options than the older ones?
we used to have a nice oxygen/vs passengers chart which would allow in some cases continued flight at higher levels (though we would have descended if pressurization were lost).
j