...And run out of oxygen, letting many of the passengers DIE in the process or, in the event of an engine failure, drift gently into the terrain killing EVERYONE.
Hardly.
You are fighting above your weight here Guppy- commercial operations over that sort of terrain REQUIRE stratergies to ensure saftey.
You assume that because it is outside you experience, it does not exist.
Whereas I operate in and out of many of the locations under discussion...including afghanistan, Iraq, and other locations throughout the region, you're wrong, of course. But thank you for your insight.
Escape routes towards nominated alternates are planned from waypoints en route leading you to lower MSAs.
Not in the operation for which I fly.