Guessed the beginning, did not guess the end

[last lines]

[while in a holding cell in the back of the courthouse]

Roy: Mr. Vail?

Martin Vail: Yeah?

Roy: [stammering] Will you t-tell Miss Venable I'm sorry? Tell her I hope her neck is okay.

Martin Vail: Yeah... I will.

[begins walking away, then turns back]

Martin Vail: Wait... What did you just say? What? You told me just a few minutes ago that you didn't remember. You blacked out. You "lost time" yet again. So, how do you know about her neck?

Roy: [slow clapping sardonically; sneers] Well... good for you, Marty. I was going to let it go at that. You was looking so happy just now. I was thinking, hmmm God. But to tell you the truth, I'm glad you figured it out, because I have been dying to tell you. I just didn't know who you'd wanna hear it from, you know? Aaron or Roy... or Roy or Aaron. Well, I'll let you in on a little secret. A sort of a client-attorney-privilege type of a secret, you know what I mean? It don't matter who you hear it from. It's the same story.

[stammering as Aaron]

Roy: [in a southern accent] I j-j-just... had to kill Linda, Mr. Vail.

[normal voice as Roy]

Roy: That cunt just got what she deserved. But... cutting up that son of a bitch Rushman? That was just a fucking work of art.

Martin Vail: You're good. You are really good.

Roy: Yeah. I did get caught, though, didn't I?

Martin Vail: So there never... there never was a Roy?

Roy: Jesus Christ, Marty. If that's what you think, I am disappointed in you, I don't mind telling you. There never was an Aaron... counselor! Come on, Marty! I thought you had it figured, there at the end. The way you put me on the stand like that? That was fucking brilliant, Marty! And that whole thing like "act-like-a-man"? Jesus, I knew exactly what you wanted from me. It was like we were dancing, Marty!

Martin Vail: Guard!

Roy: [as Vail walks away] Oh come on, don't be like that, Marty. We did it, man. We fucking did it! We're a great team, you and me. You think I could've done this without you? You're just feeling a little angry here, because you started to care about old Aaron, I can understand that, but... you know, love hurts, Marty. What can I say? Hey, I'm just kidding, bud! I didn't mean to hurt your feelings! What else was I supposed to do? Hey, you're gonna thank me down the road, because this is gonna toughen you right up, Martin Vail! You hear me? That's a promise!