I agree with BBS; IMO,the greatest "What if...?" is in their return from the mountain.But I'd add also another former moment that could be decisive for their future;when they fought up to the mountain.If Jack only had joked to relief their tension but,almost immediately,they had talked instead to fight down the mountain's slope,maybe something had been arranged,or at least,known between the both of them.Unluckily,our boys were lacked of a good communication indeed...