Character mistake: Sergeant Gormley is promoted to Lieutenant in the previous episode. In this episode he is referred to as Sergeant Gormley by Commissioner Reagan and Deputy Commissioner Garrett Moore at least twice.
Character mistake: In this episode, Garrett says that "Nom de Guere" means pen name. It means war name. Nom de Plume means pen name and Garrett is supposed to be an expert in his field.
New this weekAnswer: It is an NYPD Detective Bureau lapel pin. If you zoom in on a pic of "Danny Reagan," you will see that the pin has the letters DB on it.