Desmond devises a way to save lives by tying a rope around the soldiers’ bodies and lowering them down the vertical stone cliff that borders Hacksaw Ridge, and using that technique he rescues a great many of them. Desmond Doss, who saved 75 men at Hacksaw Ridge, became the first conscientious objector to receive the Medal of Honor, and Gibson has made a movie that’s a fitting tribute to him (at the end, he features touching footage of the real Doss). But one surprise, given the drama of pacifism-versus-war that the movie has set up, is that there’s never a single scene in which Desmond has to consider violating his principles and picking up a weapon in order to save himself or somebody else. A scene like that would have brought the two sides of “Hacksaw Ridge,” the violent and the pacifist — and, implicitly, the two sides of Mel Gibson — crashing together. But that would have been a different movie. One that, in the end, was a little less safe.