Katie Findlay Katie Findlay

Sam's killer will finally be revealed on Thursday's How to Get Away with Murder fall finale (10/9c, ABC). But to hear Katie Findlay tell it, the "who" is less important than, well, the WTF.

"I think what shocked a lot of us about the way things played out was the actual nuts and bolts of it," Findlay tells TVGuide.com. "What ends up happening is very different than what people are thinking. The actual process of how Sam ends up where he ends up is messy and it takes a lot more than one person making weird calls. It's complex. I'm telling you, really and truly, the process freaked me out. It made me sick to my stomach. It'll freak you out. My hands were shaking a little bit for a couple days. It's pretty intense."

Fall TV Report Card: How is the new class doing?

Thursday's episode will unfold entirely over Murder Night, and the identity of Sam's (Tom Verica) murderer will be revealed halfway through. A lot of signs point to Findlay's Rebecca as the culprit — Exhibit A: blood splatter all over her body; Exhibit B: rehearsing her confession to Wes (Alfred Enoch) — but surely those are just red herrings, right? "I don't know if they're shooting for obvious or not, but I don't think she's too obvious to be the killer," Findlay teases. "There's a lot that we don't know, not just about Rebecca, but everyone."

Even before we saw the bloody flash-forwards, Rebecca was already atop many viewers' suspects list, thanks to her possible involvement in Lila's murder (and retracted confession) and her knowledge of Lila's affair with Sam. The enigmatic drug dealer has staunchly kept her cards close to the vest, despite Wes' eagerness to exonerate her, but last week's Lila-centric flashbacks proved she wasn't exaggerating about her friendship with Lila. "People are always asking me if Rebecca's trustworthy. I find it really interesting because what I think people are reacting to is [that] she's learned to fend for herself," Findlay says. "She moves in a different way than a lot of people on the show and it's fun for me watching everyone freak out about it and think there's something else going on. I think she's trustworthy. I just don't think we know what she's made of yet, which might be worse."

Rebecca is, at the very least, self-sufficient — to a point. Viewers haven't learned much about her broken background, and Findlay says that she knows just as little. When Findlay got the part, creator Pete Nowalk called her — "while I was on line at the bank with my mom," she notes — to tell her his vision for the character.

How to Get Away with Murder postmortem: Boss breaks down Annalise's motives and killer theories

"He was really caring and great about it. Playing Rebecca is interesting for me because she's a person without a support system," Findlay says. "It's hard to put yourself in the place of spending years without a support system when you have one. I think that's the root of [Rebecca's] confusing behavior for people. All these situations have come up before in her life and they've gone badly, like trusting people, taking responsibility. What you're seeing now is how she knows how to survive. She is reactionary. She's kind of a little bird. It's protective. She's seen some stuff, so she's not afraid to go do something. She walks a line of feeling like she can handle everything and wondering if it's gonna come tumbling [down] and wondering if it's worth it. And if this guy says he can help, in her head, she's helping Wes too."

Wes, of course, has gone from Rebecca's wannabe savior to her actual lover. But could one of them — or both of them — be playing the other? Wes wasted no time breaking his promise to Annalise (Viola Davis) by telling Rebecca about Lila's pregnancy, and she wasted no time relaying said pregnancy to Nate (Billy Brown) in their ploy to expose Sam. "I think they do love each other. In Wes, Rebecca found someone who just skipped over the things she usually uses to make people go away," Findlay says. "He's uncovered the person she used to be. I think she likes feeling like that person."

Besides, Rebecca and Wes might not be all that different. There was something slightly sociopathic, or at least alarming, about the way he calmly told Rebecca — post-coitus — about his mother's suicide, and in the same inflection-free way he named his favorite ice cream flavor. "Sociopath is one direction," Findlay says with a laugh. "It's also possible he's not used being a person who opens up and [who is] valued. As I'm learning with Rebecca, feeling valued in the world really changes how you interact, what kind of importance you see your life as having. It's something he's never talked about or worked out. Wes has his own complicated issues. He's a very dark character like she is. They actually move through the world in a very similar way."

How to Get Away with Murder's Liza Weil: Everything changes between Bonnie and Annalise

Rebecca's feelings for Wes might explain that possible confession she was practicing for Sam's murder. Whereas her false confession for Lila's murder came under police duress, Findlay believes Rebecca is "the type of person who has the compassion to cover for someone else." "But I think she's used to enduring suffering," she adds. "Whether or not she's confessing in earnest, she likes this boy. I don't think she knows how to express that. Either way, she's willing to cover for him or she's willing to justify, 'My life is a war zone all the time. I'm just gonna go down with the ship. I caused this entire mess.'"

And viewers can rest assured that someone did purposely cause said mess. Asked whether Sam's killing was an act of self-defense or premeditated murder, Findlay promises, "It's not just a mistake."

"There is a lot involved. I had to read it a couple times before I figured it out and how people were implicated," she says, before adding: "Tom [Verica] has this wonderful theory that he went to give one of us a hug and tripped and fell into a table. It was a very sad accident. Everybody would love that! I'm sure people would be satisfied!"

How to Get Away with Murder
airs Thursdays at 10/9c on ABC. Who do you think killed Sam?

VIDEO: You'll never guess what's on Viola Davis' Watchlist!

Viola Davis' Watchlist

You'll never guess what shows this Oscar-nominated actress watches!