What happens in Part 3 of "An Occurrence at Owl Creek Bridge"?
In the beginning of Part 3 of this story, Peyton Farquhar is getting hanged. He is being hanged because he has tried to sabotage the bridge.
He gets hung, but the rope breaks and he falls into the creek. As he floats down the creek, the soldiers are shooting at him, trying to kill him before he gets away. After a while, he finally gets away.
When he gets away, he heads home. He gets there, goes to hug his wife, and then he feels a huge blow and dies. He had imagined all of that stuff between when he started falling and when his neck broke from being hanged...