"Mad City: The Gentle Art of Making Enemies" is the fourteenth episode of the third season of Gotham. It aired on January 30, 2017.
With Jerome on the loose with one target in mind, Bruce and Alfred's safety is compromised. Meanwhile, Gordon's uncle Frank pays him a visit, and Nygma and Penguin are forced to confront their issues face-to-face, with possible deadly consequences.
The episode takes inspiration from the acclaimed comic book Batman: The Killing Joke by Alan Moore.
Bruce Wayne decides to spare Jerome's life and makes a promise that he will never take a life. This is a major part of Batman's character in the comic books as well as many other adaptations of the character.
The episode also plays a couple of homages to Frank Miller's comic book The Dark Knight Returns. The standoff between Bruce and Jerome in the glass house is a reference to this, such as Bruce using the mirrors to lure Jerome and cause him to fire upon them, a tactic Batman used against the Joker. Also prior to the glass house standoff, Jerome refers to Bruce as "darling", which Joker also did in The Dark Knight Returns by calling Batman the same.