For why does that sound like a watch enveloped in cotton?
For what had I to fear?
I must scream or die!
"Much such a sound as a watch makes when developed in cotton" (Poe 83). This is a simile because it uses the word "as" to compare a sound to the sound a watch makes when developed in cotton
"I went down to open with a light heart,---for what had I now to fear?" (Poe 82). This is a tough question because he's going to have to deal with the cops but he thinks that he hid the body really well that they won't find out.
This shows that the narrator is guilty for killing the man. So, because of his guilt, he decided to give himself away to the police. The police didn't know he killed the old man until he confessed though.