Kitty phones Reardon to arrange a meeting with him at the Green Cat Restaurant on Salton Street. [She plans to seduce and then set him up for extermination by the same killers that murdered the Swede.]. But he proposes that she meet his go-between representative first - "a man...blue suit, bowtie" - outside the lobby of the Adelphi Theatre. The marquee outside the theatre reveals an in-joke:

A hood with a cane (Ernie Adams) shadows Reardon (posing as 'the man') as Kitty appears, asks "Got a match?", and spots the bowtie. They take a cab to the Green Cat, as ominous 'Dragnet' music identifies the appearance of Colfax's two killers Al and Max following behind.

Kitty: I thought you didn't like the Green Cat.
Reardon: Only when I'm not expected.

Kitty claims she flew on the first plane to Pittsburgh to meet him. Mirrors line the back of the restaurant, decorated with a giant feline statue. The two sit at a table in the rear and order from the waiter:

Kitty: A glass of milk, hot. I haven't eaten all day.
Reardon: A steak sandwich, rare, and a glass of beer.

Reardon identifies himself as an insurance agent and bluntly asks Kitty where she has the $254,912 payroll hidden. She refuses to give up all the loot, and rejects making Colfax the "fall guy":

Kitty: Can you put me away, Mr. Reardon?
Reardon: Blinky Franklin made a deathbed statement under oath. There's no stronger testimony. And there's a chambermaid in an Atlantic City hotel that has a memory for faces. Well?
Kitty: Oh, there's no use kidding myself. I'd do anything you wanted. Give you every penny I could lay my hands on.
Reardon: How many pennies is that?
Kitty: Well, I might be able to raise $65, $70 thousand at the most.
Reardon: Not enough.
Kitty: That's all I could possibly get together. I'm not stalling, Mr. Reardon, not now. I know when I'm beaten. I'm fighting for my life, not Kitty Collins' life, but mine. I have a home now and a husband. I've got a life worth fighting for, and there's nothing in this world I wouldn't do to keep it just the way it is.
Reardon: Well, we might still be able to do business if you put a prize in with the CrackerJack.
Kitty: What do you mean?
Reardon: I wanna fall guy when it's over.
Kitty: Who would that be?
Reardon: Colfax.
Kitty: Even the old Kitty Collins never sang, Mr. Reardon.

When she is uncooperative, Reardon threatens to immediately speak to the police, so Kitty agrees to freely comply. She admits that Colfax planned the robbery and describes the Swede's obsessive love that she cleverly manipulated on the eve of the heist:

I hadn't seen him for a long time, but the minute I laid eyes on him, I knew. He was always looking at me. And it doesn't sound like very much, but he always carried a handkerchief I'd given him...I hated my life, only I wasn't strong enough to get away from it. All I could do was dream of some big payoff that would let me quit the whole racket. The Swede was my chance to make my dream come true. If I could only be alone with him for a few hours. But Colfax was always there. I thought it was hopeless. Then suddenly, my chance came.

Eleventh Flashback:

In the film's final - and crucial - flashback, Kitty recalls delivering news from Colfax of the rendezvous location change - BEFORE the half-way house fire - to the gang members:

Colfax sent me to tell the others what had happened and that they would meet at the farmer's instead. I went to Blinky Franklin first, and then to Dum Dum. I saved the Swede 'till last. It was nearly two in the morning when I got there.

It is one of the few times that an unscrupulous Kitty is alone with the vulnerable Swede, and she takes full advantage of the opportunity. After telling him of the location change, she deliberately misinforms him that he will be cut out of his fair share. She even admits her poisonous, lethal nature ("I'm poison, Swede, to myself and everybody around me"), while promising the Swede that the money will allow her to get away from her hated boyfriend (another major lie):

Kitty: I'm taking my life in my hands coming to you like this, but I just couldn't stand by, not after what you did for me that time in Philly.
Swede: Forget that. Why are you here now?
Kitty: Colfax thinks I'm on my way to New York. He's meeting me there tomorrow. But I just had to come to you, Swede, and tell you.
Swede: Tell me what?
Kitty: (She removes her outer coat) They're planning to double-cross you.
Swede: (He grabs her by both arms) Who is?
Kitty: Colfax and the others. They don't intend for you ever to get a smell of the money from tomorrow's job.
Swede: How do you know that?
Kitty: Colfax sprung it tonight on Dum Dum and Blinky right after you left. First, he called you names and said dirty things about you. And then he sprung it. What if they were not to go to the half-way house after the robbery? You'd go there, but they'd be someplace else, and so would the money.
Swede: What did Blinky and Dum Dum say?
Kitty: They fell right in with the idea.
Swede: Where are they gonna meet?
Kitty: The farmhouse north of town on Polk Road, eleven miles out on the turnpike. Colfax hates you, Swede, so much so that Blinky and Dum Dum have caught it from him and they hate you too.
Swede: Thanks for putting me wise, Kitty.
Kitty: What are you gonna do? Swede - what are you gonna do?
Swede: I'm gonna do them like they mean to do me.
Kitty: Promise me one thing. You won't give me away. If Colfax ever found out what I did...
Swede: Don't you worry.
Kitty: You know why Colfax hates you? Because of me. He's no fool. He sees what's happened.
Swede: Why did you ever go back to him, Kitty?
Kitty: Maybe because I hate him. I'm poison, Swede, to myself and everybody around me. I'd be afraid to go with anyone I love for the harm I'd do them. I don't care harming him.
Swede: (He pulls Kitty into his arms) You're not meetin' him tomorrow.
Kitty: All right, Swede. (They embrace and kiss passionately)

According to Kitty, the Swede carried through on the plan and met her after leaving the farmer's place, and they drove down to Atlantic City. After luring him there, the two-faced Kitty ditched him after two days:

As soon as you could break away, you left him flat. I'd like to have known the old Kitty Collins. You were in the clear because no one knew you'd been with the Swede. You had nothing to fear from anyone. Too bad it had to catch up with you now.

Claiming that she's nervous, Kitty retreats to the ladies' room to elude Reardon, as the two killers approach (with appropriate 'dum-de-dum-dum' underscoring) to ambush Reardon. But Lubinsky shoots them dead in a short and violent gun battle. Kitty escapes through the powder room's window during the confusion - but Reardon knows where to direct the police - to Colfax's Pittsburgh mansion.

As their dark silhouettes approach Colfax's front door and everyone cautiously enters, five shots are fired - not at them, but between Dum Dum and Colfax on the stairs landing. Dum Dum collapses dead at the foot of the stairs, and Colfax lies dying on the upper level of stairs - shot by Dum Dum for planning the heist (with double-crossing Kitty) and absconding with all the money. Reardon figured out the tiny flaw in Colfax's heist betrayal from something Dum Dum told him:

He (Dum Dum) said Kitty brought him word at midnight about the changed meeting place. The half-way house didn't burn down 'till nearly three in the morning. That meant Kitty had a partner. And who could it be but you.

Kitty appears after being apprehended outside by the police - and is revealed to be Colfax's wife and partner in crime. While dying, Colfax explains that he had the Swede killed to silence him from telling Dum Dum and Blinky that he had stolen the money with Kitty (because the thugs knew that he and Kitty were married).

She kneels by her husband's body and again expresses how heartless and selfish she is, by repeatedly begging her dying husband to lie for her (as the Swede once did), to save her from serving prison time, and to declare her innocence about the hired killers. But Colfax, her potential fall guy, expires after asking for a cigarette. His silence criminally implicates Kitty and condemns her:

Colfax: I guess our luck's run out, Kitty. (To Reardon) You didn't have anything on her before now, did ya?
Reardon: No, but I had to make you think so. And I was sure you'd try to knock me off before I could find out Kitty was your wife.
Colfax: You knew that too, huh?
Reardon: Married people can't testify against each other. Otherwise, I would have tried playing you off one against each other, instead of making myself a target for those gunmen of yours...
Lubinsky: What I don't get is, why you sent those two killers to blast the Swede? He wasn't doing ya any harm there in Brentwood. Why didn't ya let well enough alone?
Colfax: I couldn't. Suppose one of the gang ran into him, same as I did. They were after the money, if he had a chance to tell his story, and that would've been the end of it. They knew Kitty and I were married and they've seen through the frame-up. Anyhow, if I hadn't had him knocked off, he would've wondered why, and begun thinking.
Kitty: (desperately) Jim! Jim!! Tell 'em I didn't know anything. Jim, listen to me. You can save me. Jim, do ya hear me? Tell them I didn't know those gunmen were coming. Say, 'Kitty is innocent. I swear, Kitty is innocent.' Say it, Jim, say it! It'll save me if you do.
Lubinsky: Don't ask a dyin' man to lie his soul into hell.
Kitty: 'Kitty is innocent. I swear, Kitty is innocent.'
Reardon: It's no use, Kitty. Your would-be fall guy is dead.
Kitty: Come back, Jim, tell them. Come back! SAVE ME! Jim! 'Kitty is innocent! I swear! Kitty is innocent! Kitty is innocent! I swear, Kitty is innocent! Kitty is innocent!'

[Ironically, Colfax also stole the money for the duplicitous Kitty, as the Swede had done, and ended up dead.]

The final brief scene plays out in Kenyon's insurance office, where the insurance chief describes how Colfax and Kitty, the film's second set of 'killers,' planned the ultimate frame-up to allow them to keep the entire "take" of the heist:

And the Swede never knew his girl had gone straight back to Colfax with all the money. As for the others, they had no idea she'd ever been away from Colfax...And Colfax framed the whole thing, just so he wouldn't have to split the take.

Reardon wraps up his own findings about Kitty's smoldering triple-cross:

The double-cross to end all double-crosses!