Mr. Monk Goes to the Hospital - S5-E16
Revealing mistake: When Monk and the others are examining the crime scene, the "corpse" can be seen breathing (his abdomen is rising and falling) and blinking. There are various shots in this scene taken from behind the body looking into the room, and some of these are pulled back so that the body is visible while others are zoomed in so that it is not; this is not a mistake, but suggests that maybe the actor was told he would not be visible in these shots and so did not need to hold his breath.
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