When Benjamin (Mel Gibson) and his two sons liberate his other son from the twenty soldiers, just before the screen goes black, look at the horse carriage driver. He isn't dead, he just pulled up.
If you were really paying attention to the movie you would notice that a few scenes later a wounded soldier laying in a hospital bed tells Colonel Tavington that he was the only survivor of the attack...maybe he was suppose to lift up his head....this is the scene that Ben Martin is first referred to as "the ghost"