How we cite our quotes: All quotations are from The Departed.
Quote #1
COSTELLO: When I was your age, they would say we could become cops or criminals. Today what I'm saying to you is this: When you're facing a loaded gun, what's the difference?
Costello has his own way of looking at things, especially criminality. For him, the world is just full of a bunch of people with guns trying to take control of that world. There's not much difference for him between cops and criminals—it's just different people with different guns.
Quote #2
ELLERBY: This is an elite unit. Our job is to smash or marginally disrupt organized crime in this city
Captain Ellerby has a fun sense of humor, which he needs to have to do his job well. Like many cops, he knows he'll never fully stamp out crime in his city. All he can really do is disrupt it a little.
Quote #3
ELLERBY: And by organized crime in this city, you know who we mean.
Ellerby doesn't bother telling people what they already know. Everyone in the police department knows that Frank Costello is the head of organized crime in Boston. The funny thing is that everyone can know this, and Costello can still be out on the street running his gang. But that's just because Costello knows how to play the system to stay out of jail.