Walking Dead's Sarah Wayne Callies: Lori's Afraid Rick and Shane Might Kill Each Other

The secret is out!

In last week's episode of The Walking Dead, Lori (Sarah Wayne Callies) finally came clean to Rick (Andrew Lincoln), not just about being pregnant, but also that she had had an affair with his best friend Shane (Jon Bernthal). (To be fair, they both thought Rick was dead.)

The Walking Dead Boss: Shane's living on borrowed time -- but hasn't worn out his welcome yet

Now, Lori and Rick will face a challenge more treacherous than ravenous zombies: saving their marriage, a task complicated by Lori's pregnancy. Is it Rick or Shane's kid? TVGuide.com chatted with Callies to get her take on the venomous threesome.

Now that Rick knows about the affair, how will that change things between them?
Sarah Wayne Callies: Andy and I have been playing with the idea for a while that Rick has known for a long time and it was a test of whether or not Lori would be honest with him and when and why. It actually opens the door for things to begin to heal for them. He deeply needed to hear her say that she thought he was gone. She wasn't secretly burning a candle for Shane for the last eight years of their marriage.

You say he needed to hear that, but do you think that's the truth? Lori doesn't have any feelings for Shane?
Callies: I don't think Shane ever crossed Lori's mind as anything other than a dear friend until she was in his arms the night that Atlanta fell. There's something about memory that's really tricky, that when you go back to an event in your mind, it can actually change. Lori's having a much harder time putting it out of her mind and putting Shane out of her mind than she ever would've anticipated, given that it was really just a purely physical thing at its inception.

Walking Dead's Robert Kirkman: Lori's surprising results are only the beginning

How will Shane react to the pregnancy? Will he assume it's his?
Callies: That's her biggest fear right now, because there's no way to be sure whose baby it is, unless it turns out that she's two months pregnant and it happened before Rick was shot. But at this point, there's no timeline, so she's really afraid. Quite frankly, one of the reasons that she considered terminating the pregnancy is because it has the ability to tear these men apart, and that has huge implications not just to her personal life, but to everyone's safety. There's a part of her that's afraid they might kill each other. This is the kind of thing men kill each other over.

What will Shane do to cement himself in Lori's life?
Callies: For a while now, Shane has been trying to protect her and Carl (Chandler Riggs), and has been doing that from a distance and trying to take Rick's place. He's posturing. I'm thinking of the Planet Earthfilms, where the men of a species are trying to demonstrate to the females that they're bigger, stronger and better. Shane has a new level of investment in Lori's safety, if he does believe it's his child that she's carrying, and that means Rick's protection of Lori has to be that much more complete. It all gets very futile. At a certain point, this culture has devolved into a place where, as a woman, maybe you have to decide who you're with based on who can keep your child alive, rather than who's the best communicator, or who makes the best spaghetti Bolognese.

The Walking Dead: Can the survivors coexist with the family at Hershel's farm?

The Walking Dead's community hasregressed to caveman-like conditions. Who can build fire? Who can protect you? That's who you should be with.
Callies: That's exactly right. We talked a lot in the first season about a certain Camelot prospective. You have three people who really do love each other equally. The longer we go on, the more it feels medieval, where there are moments where Lori looks at these guys and goes, "Jesus Christ, if I'm not careful, one of you is actually going to throw me over your shoulder and ride off on a horse with me." [Laughs] It's kind of amazing, especially coming from a woman who six weeks ago was driving a station wagon and shopping at Walmart.

Will Rick use Lori's pregnancy as a card to play to be able to stay on the farm?
Callies: The effect it has on him is more about the need to stay, not just because there's safety, but the need to stay close to the only person who practices medicine, veterinarian or no, and the need to make things right with Hershel (Scott Wilson) and the need to be able to make a home there. The pregnancy heightens all of that because Lori is not going to be able to run forever. There's a time bomb growing in her.

The Walking Dead's Laurie Holden: Andrea greatly admires Shane

How will the survivors deal with the barn in the midseason finale?
Callies: It speaks a lot to what we were discussing before about Rick and Shane. When people find out what's going on, there are very different perspectives on how we should proceed because there are different perspectives on what the true danger is. Is the true danger a bunch of walkers in the barn? Is the true danger Hershel throwing us off his farm? Could Hershel even do that? We outnumber them, we're armed, and who do we become if we make that kind of decision? Those become the questions that are raised with the barn and it deeply, deeply, deeply divides people. The whole thing blows sky-high.

The first half of the season is interesting because you have the illusion of safety for a minute, for a few episodes. You have people experiencing the problems you'd have when you're not necessarily running for your life every second. What the barn does is bring us back into a world where everybody realizes that we're not safe and we're not going to be safe. While it's the end of the first segment of the second season, the second half of the season has a very different character because of what the barn represents and how the situation is handled.

The Walking Dead's midseason finale airs Sunday at 9/8c on AMC.