I'll move past that point and look at some other things in the story. Montresor does do a good job of luring Fortunato in without even asking him to help him out. In fact, the entire time he's telling Fortunato not to help him out, but Fortunato's obsession with wine, and himself, refuses to let him quit and go back; he has to be the one to tell Montresor whether it is true Amontillado, not Luchresi. It's the perfect reverse psychology.
The story is riddled with symbols and parallels between Montresor's family and his inevitable revenge. His family's motto is "No one attacks me with impunity", which means no one attacks me and escapes punishment. The family symbol is a snake getting stepped on, but the snake's teeth are sinking into the man's heel at the same time, once again symbolizing that revenge that Montresor will get on Fortunato. Finally, the wine is called "De Grave", which is like the grave that Fortunato is heading to.
At the end, right before Montresor puts in his the last stone to Fortunato's tomb, his heart grew sick. Maybe he realized that he was about to take a man's life in cold blood? He shouts out his friend's name at the end, I'm not sure why, but it's almost like he felt a little bit of Fortunato's pain. What makes the story so disturbing in my opinion is that he feels that pang of regret at the end but still goes through with it anyway.
I gotta say this story bugged me a little. Edgar Allen Poe is one weird guy.