Fortunato, I have some wine that I need your help with.
Montresor is luring Fortunato into his vaults.
Nemo me impune lacessit.
Montresor leads Fortunato further into his vaults.
Montresor and Fortunato near the vault.
The wine is just past a few more doors
Montresor locks Fortunato inside the vault, where he will eventually die.
What are you doing?!?
I am going to leave you in there for hurting me.
It is ironic that Montresor says "Nemo me impune lacessit" which means no one attacks me without being punished, and in response to this, Fortunato says good. What Fortunato didn't know is that Montresor was saying that to him, and he was going to punish him.
Since Fortunato didn't know he was talking to him, he thought nothing of it, but since we know what is going to happen, it was verbally ironic and had a hint of foreshadowing since Fortunato didn't know what he meant, and that it led to Fortunato being punished.