The Story: The thing is it's comedy.Dirty Harry is a police procedural based on the true-crime "Zodiac" killings in San Francisco with a slant against lenient criminal rights in favor of victims' rights (which is why liberal Don Siegel agreed when his buddy Clint Eastwood asked him to direct it). Bad things happen. But there's a gallows humor that runs all the way throughout, and Clint Eastwood was an expert at gallows humor. It's something he exploited during the Sergio Leone years when he insisted on cutting dialog that he could convey with just "the look." In this scene, he employs variations of "the look" and a good use of posture to evoke the cruel humor (and a quirksome curiosity) of his "Dirty Harry" Callahan.
Here, a seemingly peaceful San Francisco noon-hour is disrupted by a bank-robbery. Harry sees it before it happens. But, he's content to just call it in and eat his hot dog in peace. And its comedy that at the precise moment he starts eating the alarm-bells go off. He's still chewing when he un-holsters his pistol, and when he shouts "Halt!" it's in a spray of spittle and bun.
But beyond that, this is a prime example of the economy and meticulous staging of director Don Siegel. There are a lot of cuts, but none of them extraneous. When Siegel cuts away, it's not to provide another angle, it's to raise the stakes. Mostly, he shows the innocent by-standers...in the case of the painters they're trapped and can't get out of the way...that raises the stakes for Callahan and forces him to expedite matters in the quickest way possible. This sequence, shot on the Universal lot (rather than the San Francisco locales in which the rest of the film is shot), lets you know where everybody is and what's at stake...even if they show up in the corner of a frame. Siegel tells you who's where and who's in the line of fire. He lets you look over Harry's shoulder to see the waiting get-away car in the restaurant window.
And at the end, he gives you a long shot of Harry meandering down the street in the middle of all the havoc that has been wrought. "Dirty Harry" evokes "High Noon" a lot, with that walk down the street by the one man who'll get involved, by the innocents who can only stand by and watch, and by the film's final shot.
But mention must be made of one other actor in this scene—and its not Woodrow Parfrey who plays the cook. Albert Popwell was a dancer who then pursued a career in films. He's the bank robber who's "gots to know." He'd appeared in Coogan's Bluff with Eastwood, and he became something of a running gag in the "Dirty Harry" movies. He played a pimp who gets shot by vigilante cops in Magnum Force, a black militant who gets shot by the bad guys in The Enforcer, and finally, in Sudden Impact, he plays Harry's fellow officer...who gets shot. He was such a fixture in the "Harry" movies that he was missed in The Dead Pool.
The Set-Up: Just another day for Inspector "Dirty" Harry Callahan (Clint Eastwood). He's on his way to lunch, when he spots a running car parked outside a bank with a large collection of cigarette butts along the driver's side. Probably a robbery in progress, but if he times it right he won't have to get involved.
Shyeah! Right!
Action!
Customer: Thank you!Jaffee: Inspector Callahan!
Harry: Jaffee...the usual.
Jaffee: So..the usual lunch or the usual dinner?
Harry: Well, what difference does it make?
Jaffee:(smiles) Not much.
Harry: Hey, Jaffee, uh...is that tan Ford still parked across in front of the bank?
Jaffee: Tan Ford....
Jaffee: Mm-hmm. Yeah.
Jaffee: Tan Ford.
Harry: Engine running?
Jaffee: (chuckles) I don't know. How can I tell?
Harry: Exhaust fumes comin' out of the tail-pipe?Jaffee: Hmph. That's awful.
Jaffee: Look at that pollution.
Harry turns.
Harry: Yeah.
Harry: Do me a favor, willya? Call this telephone number?Harry hands him a card.
Jaffee: Police department?
Harry: Yeah. Tell 'em Inspector Callahan thinks there's a 2-11 in progress at the bank. Got it?
Jaffee: 2-11.
Jaffee: Got it.
Harry: Be sure and tell them it's "in progress," right?
Jaffee: "In progress." Yes, sir.
Jaffee starts to call.
Harry (to himself): Now...just wait 'til the cavalry arrives.
Harry takes a bite of his hot dog, and doesn't even have a chance to chew before an alarm across the street rings.
Harry: Aw, shit!
Harry: Halt!
The gunman fires. Harry fires (1) and knocks him off his feet.
A second rubber runs out of the bank fires and throws himself through the window of the Ford. Harry fires again.(2)
The Ford begins to careen down the street weaving slightly and coming straight for Harry, who's in the middle of the intersection.
Harry fires at the Ford. (3)
Its windshield shatters, and the driver, mortally wounded, falls over, spinning the steering wheel.
Harry fires again, (4) and the car veers into a fruitstand, and over a hydrant—a geyser of water knocks the car onto its side in the middle of the street.
The second gun-man, shaken, drops out of the vehicle and fires at Harry, who returns fire...(5)
...knocking the second gun-man into a shop-window. 
It's then that the crowd begins to react to the mayhem, which has only taken seconds.
Harry looks down and notices that he's been hit in the leg by buck-shot.
Still chewing his hot dog he walks across the street to the first gun-man lying on the sidewalk, wounded, his shot-gun inches from his hand. He looks at it and Harry speaks:Harry: Ah-ah...
Harry: I know what you're thinkin': "Did he fire six shots or only five?"*
Harry: Well, to tell you the truth, in all this excitement, I've kinda lost track myself.
Harry: But being as this is a .44 Magnum, the most powerful handgun in the world,
Harry: ...and would blow your head clean off...
Harry: ...you've got to ask yourself one question: "Do I feel lucky?"
Harry: Well, do ya, punk?
Bank Robber: Wait!
Bank Robber: I got's to know....
(Harry's gun hammers on an empty chamber.)
Bank Robber: ...Sonuvabitch...
Dirty HarryWords by Harry Julian Fink & Rita M. Fink and Dean Riesner and John Milius
Pictures by Bruce Surtees and Don Siegel
Dirty Harry is available on DVD from Warner Home Video.