While season three of AMC's monster hit The Walking Dead started silently, it ended with a literal bang, culminating with the death of a beloved character in both the TV and comic series on which it's based.

Opening the year with a time jump and skipping over winter after Rick's (Andrew Lincoln) group was displaced from Hershel's farm, Glen Mazzara set out to do something different in the first minutes of the season. The first five minutes of the zombie drama's return was free of dialogue -- a scene the now former showrunner had been kicking around for some time.

Part of the decision, he tells The Hollywood Reporter, was partially to silence those who said the survivors spent too much time chatting and to show just how much the group had bonded in the time that had passed.

The season finale, meanwhile, featured a death so surprising it left diehard fans of Robert Kirkman's comic series stunned after Laurie Holden's Andrea -- a character now romantically linked to the series hero, Rick Grimes -- was forced to end her life or risk transitioning to the undead.

Here, Mazzara breaks his silence on the bloody season finale and shares his thoughts on the tricky silent opening and just why Andrea had to die.

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The Hollywood Reporter: You're submitting the season-three premiere "Seed" for Emmy consideration. What was your toughest scene to write from that?

Glen Mazzara: What I love about "Seed" was it was so much fun to write. There was a lot of joy in that script. I was really excited about the season. We never really use the word "reboot," but we wanted to advance the characters, and I wanted to show some development of those characters because I knew we were skipping the winter [between seasons] and had to show emotional growth. One of toughest scenes to write was the five-minute opening sequence. The concept was that our group has evolved into a well-oiled machine -- a strike force, if you will -- and they are picking up each other's cues like cops busting in on a drug raid. To do without dialogue, and to do it all through movement and body language, was fun and challenging but tricky. We had to make sure everybody had something particular and special for their characters -- everybody had a role -- that they weren't necessarily interchangeable. Everybody had a function on that team and that Rick was driving all of it. We also had to show that Carl (Chandler Riggs) had advanced. What was the relationship between Rick and Lori (Sarah Wayne Callies)? I wanted to push Daryl (Norman Reedus) front and center and have him as a strong No. 2 for Rick, yet we also wanted to show tension between the characters without making anybody unlikable. With any season premiere, you hope that new audience is going to show up. And for the audience to learn who all these characters are and what their relationships are without any expositional dialogue was tricky. Director Ernest Dickerson shot it in little pieces over a day or two. Fortunately, with the season premiere, you have extra time for prep and everyone's refreshed from hiatus.

THR: What was your writing process for that dialogue-free opening?

Mazzara: That was some of the most fun I've ever had writing in my entire career. I carried that scene around in my head for a long time and then sat down and wrote it out by hand in a spiral notebook. It's pretty much what I wrote initially. It just felt right to me and really landed because it was about characters. I also wanted to throw somebody a surprise. We didn't talk about doing it wordlessly when I was talking to the network or to other producers. When I wrote it out, I felt like I didn't need any words to tell this story. One of the things I wanted to do in season three was really push the filmmaking. We'd been doing that, and I really wanted to tell the story in a visual way and not have any dialogue. Plus we'd been getting hazed a bit about our characters talking too much, so I wanted to push the opening scene without any of the characters saying a word.

THR: Looking at season three as a whole, you've killed off a few major characters -- including one who's still alive and kicking in the comics. What was the decision like to kill Andrea?

Mazzara: They're all difficult decisions. I thought it was important that we always show that no one is safe. It's also important to show the effect that these deaths have on our other characters. Andrea's death, for example, I knew Rick was going to finally open up the gates of the prison after a season in which he's trying to hide away from the world and lock everybody away and keep them safe. He realizes what that means -- that our group is now becoming isolated and will be picked off, that his own son is on the road to becoming the Governor (David Morrissey), so he has to open up the gates and let other people in and be compassionate. At the end of the finale, he brings in these women, children and elderly people and the group is going to transform. There needed to be a blood sacrifice for that, and there had to be a price that was paid. Andrea paying that price was important. She is unable to re-enter the group. In a way, a lot of what she did was bring the two groups together. But she's never able to enter the prison and be reunited in a full way with Rick's group. That was an ultimate sacrifice that was worthy of the season finale.

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THR: When did you know Andrea would pay the ultimate price?

Mazzara: It developed throughout the season. I always knew that Rick opening the gates and letting people in was always a plan. The idea of Andrea's death emerged halfway through the season.

THR: What kind of feedback have you gotten about killing Andrea?

Mazzara: I've heard a lot of positive feedback, with a lot of fans thinking it was a great finale. Let's not forget it was a top show on cable and obviously a lot of people showed up. Most people found it was satisfying. There's a very vocal group saying that they're dissatisfied with Andrea's death, which shows that her death meant something; it affected people emotionally. I don't give people credence if after running the show for 29 out of 35 episodes people are surprised that I deviated from the comic book. I've never once said I was sticking to the comic book. The show has never struck closely to the comic. In episode 35, if we have a surprising death, it's in line with everything I've always delivered.

THR: What advice do you have for new showrunner Scott Gimple?

Mazzara: I'd tell him to write what he believes in.

Email: Lesley.Goldberg@thr.com; Twitter: @Snoodit