I could see a scene like the following happen in one of the new "Batman" films (I modeled it after a similar exchange from "The Mask of Zorro")...
Batman is atop the Gotham Police headquarters, as usual, for another night of reflection on the injustice plaguing the city. Crouched on the roof like a gargoyle, he hears a suggestive cough, and rises. Turning around, he's face to face with Lt. James Gordon.
Batman: "Lieutenant."
Gordon: "Batman."
Gordon smokes a cigar, bit by bit, lost in his own thoughts.
Gordon: "You know, when I first spoke about escalation, I have to be honest. I hoped it'd never get any worse. But the streets flooded with crime, people being murdered in broad daylight...and I sometimes wonder, are we doing enough?"
Batman: "I've said it before. People need dramatic examples to shake them out of apathy. You, me, and the few loyal citizens out there...are that example. Alone, we can be destroyed. United, we stand a chance of turning Gotham around."
Gordon: (sighs) "Tell me...why do you do it? Why help us?"
Batman: "Someone has to. I'm the only one they still fear, and I'm not afraid to use that fear against them. People like them made me who I am..."
Looking Gordon in the eye, Batman continues.
Batman: "...and people like you...gave me back what hope I have left."
Gordon: "Why are you so eager to help us...and why me?"
Stepping closer, into the shadows, Batman reaches for the back of his mask...
Batman: "Because once...a long time ago..."
(the mask comes off)
Bruce Wayne: "...you did the same for me."
Gordon:"Bruce..."