If operating IFR, then ATC will have a large part to play in this accident.
When would ATC give clearance in mountainous terrain below MSA unless for emergency reasons? Other than when established on the approach.
My understanding is that they are responsible for your terrain clearance while IFR. It is our responsibility to comply as far as able with those requests.
I would hardly think the approach would take them up a mountain valley when the is obviously clear ground either side of the mountain.