 The movie depicted the camp lit up with various lights. According to  one of the Rangers still living who participated in the raid, there  were actually no lights in the camp, and from intelligence, they  knew exactly when they would have moonlight. The Rangers only moved  in under cover of darkness, with the Japanese watch towers in their  view the whole time, and the moon came up shortly after the shooting  started and that was the only light they had to work by.