True-true, and indeed I had no intention of alarming you unnecessarily- but you shall use proper caution. A draft of this Medoc will defend us from the damps,
Your health is precious... you're a man to be missed.
"'A Mason? I replied. A sign? He said. It is this, I answered, producing a trowel from beneath the folds of my roquelaure." The trowel demonstrates foreshadowing because it is a clue of what might happen in the future. he also suggests masonry which is another clue to what is yet to come.
"Nemo me impune lacessit," is Montresor's family motto. It's a foreshadow because it applies that Montresor has a need for revenge and will do anything to punish one who punished him. And knowing that Fortunato insulted Montresor, this concludes that something might happen in the near future. Possibly to Fortunato.
I demand you must not leave in my absence.
"I shall not die of a cough," stated Fortunato. "True-true, and indeed I had no intention of alarming you unnecessarily- but you shall use proper caution. A draft of this Medoc will defend us from the damps," says Montresor. Montresors acknowledgment to Fortunato is a clue to what he has in mind. The fact that he wants Fortunato to drink more to "defend them from the damps" concludes that they could end up in a dark and dense and stale-aired environment later on.
I shall not die of a cough!
"Your health is precious... you are a man to be missed." Montresor does not mean what he said; instead, he wants revenge on Fortunato and wants to kill him. In other words, he does not care about Fortunato's healthy he's not going to be missed by him.
One example of situational irony is when Montresor demands his servants not to leave while he is gone. However, he knows that they will do the opposite of what he orders them to do, which makes this ironic.
While Montresor and Fortunato were talking about his well-being, Fortunato makes a statement that he will not die of a cough and Montresor responds by saying "true". This is dramatic irony because as a reader, we know that he will not die of a cough, but something much more horrific.