Answer:
Irrational behavior, an unexplained event growing and growing suspense.
Step-by-step explanation:
Edgar Allen Poe's poem "The Tell- Tale Heart" is about an unnamed narrator who killed a man but claims his sanity. He had hidden the body of the victim by cutting it in parts and hiding them underneath the floorboard. This poem is his story telling, his attempts in trying to prove his sanity. The excerpt in the lines provided in the question contains certain features such as irrational behavior f the narrator, the unexplained event that seems to be approaching and the growing sense of suspense that is built up. These factors give the whole story/ poem a gothic feeling, sort of a gothic literature feel.