She finished her shift at the dog kennel. Hours later, she had taken a man's life.

It was just another Saturday afternoon in August 2016 when Terra Newell, then 25, finished her shift at a dog kennel in Newport Beach.

She was looking forward to seeing one of her favourite country stars perform with a friend that night. As she pulled into her car park with her miniature Australian Shepherd, Cash, something felt off.

Her dog began to growl, and Terra spotted a man fidgeting in the back.

She initially thought he might be homeless, living in his car. But as she stepped out and headed for the exit, the man grabbed her around the waist.

Watch: Robyn Howarth on the Faraday kidnapping. Post continues after video.

"Do you remember me?" he asked, looking her straight in the eye.

It was John Meehan, her mother's estranged husband, a man Terra and her sisters had unmasked as a serial conman. A man she had feared for a long time.

What happened next would change Terra's life forever.

Despite Meehan being bigger and stronger, covering her mouth when she tried to scream and stabbing her repeatedly with a large knife, Terra fought back. She bit him, kicked upward with her sturdy work boots, and managed to knock the knife from his hand.

"I didn't give it a second thought, and I just started whaling on him and stabbing him," Terra told Mamamia's True Crime Conversations podcast.

"I knew that if I didn't fight back and harm him, he would continue to try to hurt me and possibly kill me."

Terra fatally stabbed Meehan 13 times in total. Her last blow went straight through his eye.

Of all Deborah Newell's four children, Terra was seen as the most softly spoken, the least competitive, "the sweet one who had never hurt a fly."

Yet when faced with a life-or-death situation, she found the strength to defend herself against a man who, as later discovered, had a kidnapping kit waiting in his car, complete with duct tape, weapons and cable ties.

Now in her thirties, Terra reflects on the aftermath of that traumatic day: "It's interesting because true crime, the story is never over in a sense, and I'm still learning stuff to this day."

What's changed most for her is how recounting the events affects her mental health.

"At first, when I went through my story, it was slightly triggering but very cathartic. And now I'm to the point where me just going through my attack and going through the hospital, it doesn't benefit my mental health anymore. It just triggers me further instead of helping like it used to."

The lasting impact of trauma manifests in unexpected ways. Terra explains how her brain still protects her from the full memory of the attack.

"I'm still piecing together that memory. Because trauma, the brain likes to block out the trauma that happens, so I can't see it fully, as if someone who was watching it might see it."

Perhaps one of the most surprising elements of Terra's story is how she knew what to do in that life-threatening moment. She credits her survival to an unlikely source, her love of zombie apocalypse television.

"I am a huge TV nerd. I love The Walking Dead and so that is where I learned to zombie kill John," Terra said. "I'm sorry, it's hard to say that without laughing sometimes."

Listen to the full episode below. Post continues afterwards.

What happened to Terra and her family became the subject of a wildly popular podcast called Dirty John, which was later adapted into a television series starring Connie Britton and Eric Bana, with Julia Garner playing Terra.

The family never expected their story to reach such a massive audience.

"We had lawyers on everything, looking out for our names in the news and ready to put gag orders on everything," Terra recalled. "The LA Times came to us. We really had to give it some thought because it is so personal and it is such a huge trauma, and we thought that it would just help other people."

One unexpected consequence of the podcast's popularity is how "Dirty John" has become a colloquialism for manipulative partners. This sits uncomfortably with Terra.

"It's funny because people will tell me, 'No, that's always been a term.' I'm like, 'No...'"

People now approach Terra saying they "dated a Dirty John," which feels strange to her.

"To me, 'Dirty John' was the person that I had to kill. I will always live with that... watching someone die is not something you ever want to do. If you've ever watched someone die from cancer, anything, it's sad. It's so sad. And to take someone's life personally, I don't wish that upon anyone."

She continued: "I wish I didn't have to do that, and, unfortunately, I was put into a situation where if I didn't take his life, I would have been gone from this planet. And so I had to do what I had to do. But it's not an easy thing to live with."

Today, Terra hopes to eventually move beyond being primarily known for this traumatic chapter of her life.

"I want to be a mum one day and I don't want my kids coming up to me, being like 'What were you talking about, about John Meehan?' And so I definitely am looking forward to putting this story in the past, really," she said.

Through sharing her story, Terra has connected with other survivors, including co-hosting a podcast called Survivor Squad with Collier Landry, who experienced similar family trauma. These connections have helped her see she's not alone.

"It's just crazy because you're like, 'Oh, that happens to you? That happens to me,' and you're just able to relate and honestly create a survivor squad and... have a community where you guys can not feel so alone."

Feature Image: Instagram/@terranewell