Mr. Monk Can't See a Thing - S5-E4
Continuity mistake: The firehouse's number is 53, and is seen on the various fire trucks throughout the episode. However, in an establishing shot at the opening of the episode, you can see letters for "Eng. Company 1" and "Truck Company 1" over the garage door. This is because Fire Station 1, located in Los Angeles, was utilized for filming.
Answer: The two men are trying to work out a secret deal between them without involving the union, which means the workers' interests aren't being represented and defeats the whole purpose of a union. The mayor would lose labor's support and Cusack's union troubles would just be starting.
Captain Defenestrator