This scene is from Man On Fire(2004), with Denzel Washington playing John Creasey.
The film itself is great action and from front to back, solid screen-writing. The near perfect performances from the cast didn't hurt either. It hits hard, harder than many other action thrillers, and yet it is vinsible. It doesn't send you running to the bathroom to splash water on your face before you puke -- although, one of my first thoughts on leaving the theater back then, was: Why not?
The character of John Creasey is a: psychologically brutalized antihero. In his history their glimmers, points of lights from moments of great heroics, and selfless service in defense of his country. We're never given details. We are given few military ranks or metals or achievements. John Creasey displays no regard for those trappings-- other than they are the suits of woe.
Walking through the story, scene to scene there is more than enough woe to cause discomfort. The hero of the story is in fact antihero, a drunk, a homicidal sociopath, a man that finds himself without justification. And while Creasy is forward and openly discusses his compromised integrity, his candor isn't enough to tip the morality scales in his favor far enough to warrant his continued existence. The scales are tipped, however, and this scene with Walken is the primary means by which the shift is made.
Crisey's candor is a side effect from living a life saturated with uncluttered intention, trenchant focus, and denudate tenacity. He is a man for whom any indulgence in self-deception is fatal. Functional vitality, however, after maintaining a moral mindset of this nature is not sustainable. Candor, or perhaps confession, is no longer an effective control. It might have been at an earlier time -- and the strategy, one which is implying that deflection, silence and prevarication undoubtably fell short -- after enduring the PTSD emulsion suffused through his rational awareness, Knowing There is a Problem, would no longer equate to half the battle -- or even a tenth of the battle -- back to sanity. Though, where he acquired his candor and self-acceptance was probably from multiple PTSD treatment periods.
This is good writing. Powerful. The dialog is also clean. There are no extraneous words. All of them have purpose. The movie is ~146 minutes. You have Christopher Walken -- who you know all you need to know -- and if you don't then go on YouTube and listen to him read The Raven. Then you will know enough. He can be a scary person when he gets into character.
The writing tactic used in this scene is known in the study of Influence, as the Endorsement. In psychology it's called Social Proof. Whatever you call it or why, it's has many powerful effects for characters in fiction. I don't know why tactics from Influence and Psychology are not explored more by authors. Perhaps they are, and they simply aren't named -- at least I've never heard them 'given their due' in workshops or writer's guides.
The whole scene is less than two minutes. In two minutes they've cut out the need for background and prologue -- in this spec of time, Creasy's character, who has been for the most part a drunk has-been -- a failure slowly dying. He's only really walking around out of habit. With this Endorsement Creasy is reframed into a badass of inhuman skill -- he is now a descending angel of death, wings wide open.
Using Walken is pure genius. Because with Walken, you have this seriously scary man candidly telling you -- as he finishes his lunch -- that, no, he's not scary at all. No, not me. I'm not anything special -- but Creasy, well, that man, he is an artist -- an artist who paints with all the scary colors. Not just one or two like I do. No, he uses them all. His art is death. Sure, I'm good, but -- hell I'm no Creasy.
And that ending, that last line of the scene mantels the endorsement -- because what he's really saying there is "that IS ALL there is to say" And what? you're going to argue with Walken on this subject? Really? No, the matter is closed.
After that scene, there is nothing the viewer or reader won't believe Creasy is capable of. He can kill thirty, forty people with a sling-shot if you wish -- all because of this scene. He can control the night. He can survive mortal wounds, and go swimming. Creasy has been unmade, and reborn, hallowed and enthroned. Not only can he do these things, he is washed clean and reborn, allowing the reader to feel good about cheering for him.
Walken takes care of that with one line. It's perfect. With one line, he grants Creasy absolution, and lifts him up into a glorious state of Righteous Wrath. Creasy can now kill, slaughter, torture, mame. He can shove a bomb up a guys ass and laugh in his face as the detonator ticks down to blow him apart. Doesn't matter. Creasy is sanctified -- all accomplished in less than two minutes.
No prologue. No flashback. No back story. No info dump.