Spoiler Alert: Stop reading if you haven't watched Sunday's episode of The Walking Dead! The AMC drama is no stranger to shocking deaths (RIP Shane and Dale!), but Sunday's episode packed a punch with two cast members biting the dust. After a rogue prisoner unleashed a hoard of walkers on the survivors, T-Dog (IronE Singleton) sacrificed himself for Carol (Melissa McBride) by becoming zombie chow, while Lori (Sarah Wayne Callies) succumbed to complications while delivering her baby. We caught up with Callies to get her take on the series' most heartbreaking episode to date.

TV Guide Magazine: What was your reaction when you heard the news?
Callies: I knew it was coming and on a show like The Walking Dead, you kind of assume that it's always coming. I got the episode, read it, put it down and couldn't really do anything for half an hour. And the great blessing was [director] Guy Ferland. Guy and I go back to Prison Break, I love him. He shot Jon [Bernthal]'s death, so apparently they bring him in to kill leading characters! Guy and I spoke about wanting to shoot it with enough elegance that it wouldn't be gross and have heart.

TV Guide Magazine: What was the mood like on set?
Callies: We were all a little shaken up. It was an interesting day because IronE died that morning, so my whole focus for the morning was dealing with my friend and colleague. It was difficult because Chandler [Riggs] and I hadn't really rehearsed the scene beforehand because, in a way, we've been preparing for this scene for two and a half years. I came out of the set in rehearsal and virtually the entire cast stopped by just to be there. I didn't know they were coming — we all did that for Jon — but for some reason I just wasn't thinking about it and it was really moving to look out there. Andy [Lincoln] and Norman [Reedus] were a little bit freaked out by the delivery. They've both got kids and I came out after we shot a couple takes of that and they both looked green and were kind of shaky. I took it as a compliment. [Laughs]

TV Guide Magazine: It's a very unusual death within the world of The Walking Dead: she doesn't get attacked or bitten, it's just a natural complication. How did you feel about the way she went?
Callies: Lori has more control over her own death than anyone else who dies on the show. It's hard for me because it's a death for Lori that is a victory, ultimately, for her. She got the baby to term and now she can leave this group of people with a gift of hope and renewal. That's the most important symbol you can leave them with. Lori's had this death sentence from the beginning, but the opportunity to say goodbye is a luxury most people don't have on the show and I think Lori says goodbye to Rick in a lot of ways beforehand.

TV Guide Magazine: Including that scene on the bridge at the end of episode 2, which in retrospect turns out to be the last conversation they've ever had.
Callies: Yeah, and the hardest thing about shooting that scene was not making it about that. Lori and Rick don't know that they're not going to see each other again. Andy and I built all of the work we did together for the whole third season around that scene. We're not going to look at each other and he's going to reach out and just put his hand on my shoulder. And that's the moment where you go, "they would have been OK." It's a part of why that moment means so much to Lori. She says to Hershel she expects to die so to just have that — he reached out to me! — that's enough. That was the scene that really messed us both up, and then [in episode 4] we had this look across the field and we hadn't really expected it to be emotionally as difficult as it was. I love Andy Lincoln, Andy Lincoln is going to be in my life for the rest of my life, but I'm never going to lay eyes on Rick Grimes again. We shot the scene, barely got through it and then we just met in the middle of the field and collapsed into each other for a second. I'm always fascinated by the idea of what goes through your head right before you die. There's this great Emily Dickinson poem called "I Heard a Fly Buzz When I Died," and it's all about a woman who's in the process of losing her life and the thing that grabs her attention is a fly. And I think that last thought in [Lori]'s head is "I'm really going to miss him," which is kind of oddly detached because she's going to peace, she gets to be free of this. She knows her son is enough of a soldier to survive, she knows the baby will be raised in a world where the baby will be a soldier from birth. But Rick was the last man alive and I'm really going to miss him.

TV Guide Magazine: What will you miss most about your Walking Dead costars and crew?
Callies: It's a culture on set unlike any other set that I've ever been on. We built a great community and we did it consciously. Andy, Jon and I were the first actors in town, we spent every weekend together, all of our free time going over the scripts and finding a way to work together. As more actors came into town, we brought them into that. If we're going to do a zombie show, then we all run the risk of falling flat on our faces. The only way we can do it well is by having a really safe environment so we can take big risks, look like an a--hole and fail. That is the hardest thing to create. Ten days after I'd left The Walking Dead, I was on another set and I talked to Bernthal. He's been an angel through this because he did it first and knows how hard it is. He was on the phone with me every day going into work and coming back, and the last thing he said to me before I left for Detroit to shoot this movie, he said, "Do yourself a favor and forgive everybody right now on the next set for not being the cast and crew of The Walking Dead. They're all going to be good people, you're going to love them, but you cannot walk in there expecting Greg Nicotero and Andy Lincoln because you can't do it." But I'll also miss Lori, I have loved playing her.

TV Guide Magazine: What do you think will be Lori's legacy in the group?
Callies: I think Lori and Rick evolved together from when they were very young so that he could be the gas and she could be the brakes [Laughs]. I think in a way she became a part of Rick's conscious and he's going to have to recalibrate without her. Lori was the first one to say we have to bury the dead, it's not your decision who lives and dies. Lori was the one who said things that were uncomfortable and hard to say but needed to be said. And maybe that's the voice that Rick's going to have to start hearing again.