The spark of compassion that still warms Nancy's heart sets off a confrontation in which she loses her life. Neither Fagin nor Sikes can be said to have anything resembling ethical standards, and no allowances are made for Nancy's gestures in favor of the two criminals. There is no way to pardon her violation of their merciless code. Fagin applies his twisted intelligence with uncanny shrewdness in showing Sikes how Nancy has betrayed them. He knows with whom he is dealing and how to insure the results he wants.
The aggravation and unleashing of Sikes's ferocious wrath produce a suspense that can only be dissipated by a terrible calamity. The vindictive murder of Nancy is the inevitable result. Her last moments are rendered with crushing pathos. There is rueful irony in her futile belated appeal to the power of repentance. She is even denied a last glimpse of the sun that she so seldom enjoyed. An excruciating contrast is beheld between the restorative light of the dawn and the curtained apartment where Nancy's life is snuffed out.
The sensations of Sikes after the atrocity trace the reactions of a homicide. For the first few hours, he wanders in a kind of daze, scarcely able to relate to what he has done. It is only when the return of darkness vividly recalls the deed that he feels the full implications of his position: "Let no man talk of murderers escaping justice, and hint that Providence must sleep." Awareness of guilt and the sense of danger become overwhelming. The horror of his stigma isolates him from his fellow men. The harshness of this penalty is eloquently demonstrated by Sikes's eagerness to lend his assistance during the emergency of the fire, just so he can be near other people and find momentary forgetfulness in hard physical labor. It is an unprecedented spectacle for others to receive help from Sikes, an enemy of society who has never shown anything but contempt for all humanity.
At the end of Chapter 48, Sikes is left in an ironical position: After impetuously slaying the one person who had affection for him, he is unsuccessful in a deliberate attempt to destroy his dog, whom he fears may be a threat to his own existence.
