'The Walking Dead' Season 4: Carol had no other decision, Melissa McBride says

the-walking-dead-carol-lizzie-death-amc-melissa-mcbride.jpg Warning: Spoilers from "The Walking Dead" Season 4, episode 14 "The Grove" are contained in this article.

"The Walking Dead" taught a pretty brutal lesson about life in the zombie apocalypse in its March 16 episode. You can either adapt to the world around you, or you can die in one way or another.

Such was the case with Lizzie and Mika, neither of whom were able to grow accustomed to the world around them. For Lizzie, she viewed the walkers as another evolution of life. For Mika, she couldn't bring herself to kill anything -- even things trying to kill her. That's why Mika was able to be killed by her older sister Lizzie, and Lizzie in turn needed to be put down by Carol.

Like previously stated, "The Grove" was a brutal episode. But according to actress Melissa McBride, it was a necessary one.

"It was something that had to be done in that world and under those circumstances; Lizzie in that world seemed inevitable. It would be impossible for Tyreese and Carol to move forward with Judith, who doesn't have any experience of the world before the apocalypse. It was so devastating for Carol to have to do that," McBride tells The Hollywood Reporter.

She continues, "I don't think there was really any other option. There's a lot of nature vs. nurture going on in this episode to look at. As much as it broke Carol's heart to have to do this and to realize this had to be done, when they were walking toward the flowers in that scene and Lizzie says, 'You're mad at me and I'm sorry.' You'd think she'd be sorry for stabbing her sister to death but instead she's sorry for pointing a gun at her and she just doesn't get it."

At least there was some good that came out of Season 4, episode 14. Carol finally confessed to Tyreese that she was the one who killed his girlfriend Karen, and Tyreese forgave her for it. According to McBride, this is a new start for the two.

"They trust each other 100 percent now. That was one of the reasons why it was so important for Carol to confess. She knew that she had to be able to trust the people she's with," McBride says. "He didn't kill her. Carol and Tyreese have bonded incredibly over this tragic experience and, as far as they know, the only two people. The only way to move forward is to be able to trust whomever you're with 100 percent."

While some might view "The Grove" as being a lesson that the world of "The Walking Dead" isn't safe for children, McBride clarifies that it isn't safe for " anyone."

"The ability to fight isn't a one-size fits all; everybody is different. Thematically, there's a lot said about change," she says. "The world will change you; but you have to adapt or die. It's about hanging on to that part of yourself: You can change but don't lose yourself."

Only two episodes of "The Walking Dead" Season 4 remain. The series airs Sundays on AMC at 9 p.m. ET/PT.
Photo/Video credit: AMC