With them alternating between climbing and belaying off, the fall would just be painful, probably not deadly but you still need to climb a third of a mile straight up. That requires that you be in better shape that I am in
What is the base altitude. From my experiences in the Tetons and the Rockies I can say, if you get over a few thousand feet above sea level, air starts be be hard to come by. Up around 9000' they just don't have much.
