I believe that this quote from The Cask of Amontillado is a great example of Poe’s dark humor and irony. Montressor feigns concern for Fortunato and the cough he has developed. Fortunato finally says that he will be fine and to stop worrying because a silly little cough is not going to kill him and Montressor agrees. To Fourtunto, it just seems as though Montressor has accepted to leave it alone for now, but Montressor agrees because it is not a cough that will kill him at all and he knows that. Montressor knows he will be the one killing Fortunato.