Pushkin's stories are psychologically realistic partly because his narrative tone is one of understatement. The story of the mysterious Silvio is told in stages in which the narrator himself is a bystander to the action, though he seems to wish to involve himself in it. His outsider status allows him to view and judge the motivations of the others with greater acuity than if he were a direct participant.
The trigger (no pun intended) for his interest in the story behind Silvio is the latter's declining to engage in a duel over a dispute in a game of faro. Both dueling and card games are subjects repeatedly focused on in Pushkin's work. The concepts of "male honor" and bravery are central to it as well. It's interesting that Silvio senses the narrator's disapproval of him and wants to correct this by telling him the backstory of his duel with the Count, whom the narrator meets several years later. Pushkin's approach has a special validity precisely because of the subliminal nature of communication between the narrator and Silvio.
The backstory involves two duels, in the first of which, Silvio declines to fire at his adversary. In the final duel, both men shoot wide of the mark deliberately. Pushkin seems to convey the pointlessness of dueling even while presenting in the strongest terms the willingness of men to die in a duel rather than sacrifice their "honor." All of this is described in a matter-of-fact way, without much embellishment or melodrama (so far as one can tell from Pushkin's English translators). For that reason the psychology of all three principal characters—the narrator, Silvio, and the Count—is made all the clearer. It is, of course, both unsurprising and ironic that Pushkin's own life was to end in a duel.