by GREG KING Hacksaw Ridge tells the story of Desmond Doss, a conscientious objector who enlisted in the US Army to serve as a medic during WWII. He was awarded the Congressional Medal of Honour for his heroic actions on Okinawa, where he rescued some 75 soldiers from the battlefield while under heavy artillery fire. This is Mel Gibson's first film as a director since Apocalypto a decade ago. It features a cast …