When does the encounter between Farquhar and his wife occur?

In Part III, Peyton must be sleeping while he walks, because when he wakes, he is standing at the gate of his own home. It is a bright and beautiful morning. When he moves up the wide walkway, he is aware of the flutter of feminine garments, and then he sees his wife coming down from the veranda to meet him. His wife holds out her arms to him, smiling with such grace and dignity. She is so beautiful that he cannot stop himself from reaching out and touching her. When he is about to embrace her, he feels a wicked blow at the back of his neck. An intense, white light blocks out everything around him and he hears something that sounds like a cannon. Then everything is dark and silent.

Peyton Farquhar is dead and he swings slowly, like a pendulum, beneath the Owl Creek Bridge.