Final answer:
Irony in literature often highlights a discrepancy between expectations and reality, which can be seen in narratives with unreliable narrators or situations where the audience's awareness contrasts with that of the characters.
Step-by-step explanation:
Without the context of the selection, it is not possible to determine what is ironic about the final statement. However, literary irony often involves a discrepancy between what is expected to happen and what actually occurs, or a situation where the audience is aware of something that the characters are not. Irony in literature is a complex device used to add depth to a narrative, create tension, or provoke thought. When characters such as unreliable narrators misinterpret their circumstances due to factors like mental illness, as suggested in the reference materials, it adds a layer of dramatic or situational irony. For example, an unreliable narrator may find security in something inherently insecure, such as a sewer, which could be ironic if their belief sharply contrasts with the reader's understanding of safety.