Who knows why he went down that way. But it is possible he thought he was on a shortcut.
From what I read online...his itinerary - "According to the reporting party, Dao flew into Las Vegas on Tuesday, June 11, had planned to summit Mt. Whitney on June 12, drive back to Las Vegas after summiting and catch a red-eye flight back home, to be at work on Thursday, June 13.
Perhaps he needed a quick descent to maintain his intended schedule.
