Fortunato is reveling in the carnival spirit, but it’s not enough. When he hears that Montresor has “a pipe of what passes for Amontillado,” his “energies,” as Booker would say, “have found a focus.”
Montresor is getting Fortunato really drunk. Fortunato must be taking this as a sign that Montresor is truly leading Fortunato to his heart’s desire – the best drink of all, Amontillado.
Fortunato begins to suspect that things might not be going as planned, when Montresor shows him the trowel. He has to step back, perceiving for a moment what Booker calls a “shadow figure,” some force threatening the hero. But then he brushes off his fear and continues the hunt for Amontillado.
Fortunato finally understands what Montresor is doing, and he screams, cries, and begs. He’s getting walled up in a hole. No Amontillado. He even brings up God. And Lady Fortunato. But none of this sways Montresor in the slightest.
That final jingle of bells is signal that Fortunato has accepted his situation for what it is. Only when he communicates his utter resignation does Montresor insert the final brick. Fortunato has finally “felt” Montresor, and thus Montresor can kill him. Fortunato’s final communication with Montresor is the “final act,” as Booker says, that “destroys the hero.”