The entire narrative of "Carlito's Way" is framed by its tragic conclusion, which is revealed in a black-and-white slow-motion sequence at the very beginning of the film: Carlito is shot on a train platform. The film is an extended flashback leading up to this fatal moment, making the story a study in inevitability. The central twist is not what happens, but how and why it happens.
Carlito's downfall is a direct result of two fateful decisions. The first is his unwavering loyalty to his lawyer, Dave Kleinfeld. Kleinfeld, consumed by cocaine and paranoia, steals a million dollars from his mob boss client, Tony Taglialucci, and then murders him during a botched prison escape that Carlito helps facilitate out of a sense of obligation. This act puts Carlito in the crosshairs of the vengeful Taglialucci family, forcing him to flee for his life.
The second, and more ironic, twist is the identity of his killer. After surviving a spectacular shootout with the mob in Grand Central Station, Carlito finally reaches the train platform where Gail is waiting. It is here that he is ambushed and fatally shot, not by the Italian mafia, but by Benny Blanco "from the Bronx," the up-and-coming gangster Carlito had humiliated but spared earlier in the film. The final reveal is the betrayal of his bodyguard and friend, Pachanga, who sold out Carlito's location to Benny. Benny then kills Pachanga as well. Carlito's act of mercy towards Benny, a deviation from the ruthless code of his past, becomes the ultimate cause of his death. He dies watching Gail board the train with his money, his dream of paradise realized for her and their unborn child, but not for him. His death is a poignant confirmation that in his world, a single act of compassion can be more fatal than a lifetime of violence.