Jack Kelso has one on the last case. After Monroe arranges a meeting (which is clearly a trap) with Kelso in his estate, Kelso decides to call his former Marine buddies and stages an all-out assault on the estate. After that, he shoots Monroe in his leg, looks around his office for a bit, and leaves him bleeding before he calmly leaves the estate to find Elsa.
Made even better by what he says immediately after shooting Monroe in the leg.
Jack: That's my opening negotiating position!
Better again by what he says after stomping on Monroe's injured leg while he's down.
Jack: That was my second offer!
He does all of this while bleeding from a gunshot wound in his arm, which he doesn't even acknowledge while Monroe is screaming for a doctor due to his own gunshot wound.
Cole's initial meeting with Leland Monroe, especially if you call him out on building houses on the cheap and lying about the Catalina Island promotion.
It even nets you an achievement in the Xbox 360 version!
Cole telling off Roy Earle when he speaks ill of the late Courtney.
Gameplay-wise, running over Roy Earle with a car once you find out that he ratted Phelps out for cheating on his wife with Elsa. This troper wishes that Roy Earle would get killed off in the story as well.
Cole's first introduction to Mickey Cohen. When Earle starts to introduce them, Phelps cuts him off by saying "I met his brother-in-law," and walks away. What makes it awesome is that Phelps had just gunned down Cohen's brother-in-law in the previous case. The point is not lost on Cohen.
Even Roy Earle gets one near the end of "The Black Caesar", a caretaker approaches the detectives as they attempt to enter the Polar Bear Ice Company building.
Caretaker: Place has been closed for years. Not much demand for ice, what with the new freezers...
Earle: Save it for someone who cares......do all janitors carry gats? (nonchalantly pulls out his gun and kills the caretaker before he can do anything.)
In "Fallen Idol", Cole and Bekowsky are approached by a bunch of goons who want them to help them find the guy both they and the police are looking for. Cole acts like a good cop and politely but firmly tells them to stay away. Then...
Goon: At least he's polite. Dumb, but polite.
Bekowsky: But Iím a lot less polite, you smug son-of-a-bitch. So let me put it in ruder terms that even a pair of blockheads like you might understand. The only reason that you donít have bars on your windows already is because youíre small fry, and we donít waste our time on small fry. You stay away from Bishop and you stay away from me. Is that clear enough for you, asshole? Now run along back to your boss so he can pat you on the head and tell you what good boys you are.
The Fallen Idol's entire last section, where you chase Bishop through a collapsing movie set, then have an epic shootout to protect Bishop from Guy McAfee's men, who number in the dozens, and want you, your partner, and most of all Bishop dead. This is a ''Traffic'' case.
A similar shootout happens in the DLC case A Slip of the Tongue. Phelps and Bekowsky are getting ready to storm a warehouse loaded with armed Mooks inside. While Bekowsky slips in the back, Phelps will take the front. But before Phelps goes in, he gets the attention of the goons with this immortal one-liner: