[agsnu]

Doesn't help you if the pilot flying is incapacitated by the toxic air in less than a minute, or crash in to mountains, as in the scenario posited in the video. Climbing out to an appropriate height to join the approach, reconfiguring the plane for landing etc, takes several minutes; an immediate forced 180 teardrop back to land is very challenging to execute successfully (see the tragedy at Jeju just before new year).

[rounce]

They don’t have to be incapacitated, simply having to deal with reduced cockpit visibility and/or minor impairment during an emergency while in a critical phase of flight is a significant elevation of risk.