 While filming a scene where the main tent catches fire,  John Wayne (qv) was almost killed when the set collapsed. As he  was "fighting" the fire, Wayne was to be cued by the assistant  director when to leave before the set was to collapse in flames.  Either Wayne didnt hear the cue, or the a.d. mistimed it (it was  never determined which), but the flaming set began to collapse  before Wayne got out. He escaped with just a few seconds to spare  before the entire set would have fallen down on top of him.