“An Occurrence at Owl Creek Bridge” contains a clear example of an unreliable narrator, as it becomes clear at the end of the story that Farquhar’s perception does not accurately reflect the events that have occurred. Farquhar imagines escaping from his noose, swimming down the river, miraculously evading bullets, and making it almost home. His escape seems too good to be true because it really is—in reality, Farquhar has never even escaped the noose. While the narrator is not Farquhar himself, the omniscient narration is still unreliable throughout the story because it closely recounts these events as if they're actually happening.
When Farquhar surfaces above the water after freeing his hands and neck, the narrator remarks the following:
He was now in full possession of his physical senses. They were, indeed, preternaturally keen and alert. Something in the awful disturbance of his organic system had so exalted and refined them that they made record of things never before perceived.
This highlights the narrator's unreliability, as the narration says that Farquhar is “in full possession of his physical senses” and that these senses are “preternaturally keen and alert,” which turns out not to be true. In fact, his senses couldn't possibly be heightened, since he loses connection with his physical senses in the split second before he dies, instead merely imagining that he lives. So, Farquhar’s senses are anything but in his “full possession.” He is instead in an altered state of perception that does not match reality.
While it is true that “something in the awful disturbance of his organic system” has changed his senses, the change is not as the narrator describes. Rather than exalting and refining his senses, the shock of his imminent death in the split second as he falls causes him to experience an alternate reality with false physical sensations. The unreliable nature of the narration is evident throughout Farquhar’s perceived escape up until the moment when he attempts to run into his wife’s arms only to be hit with the reality of death.
