Megan Park Went Into 'Serious Mode' Directing Secret Life Costar Shailene Woodley in The Fallout

David Livingston/Getty Images; Stefania D'Alessandro/Getty Images

Megan Park and Shailene Woodley share the same therapist, so it's only natural the Big Little Lies actress would play one in Park's emotional new film, which marks her directorial debut.

"It's actually really funny, she and I have the same therapist, we have for a long time, so I feel like we totally understood the therapist character. We were drawing on the same inspiration, the same person," Park, 35, tells PEOPLE while discussing The Fallout, which she wrote and directed.

The film, now streaming on HBO Max, tracks the grieving process of teen Vada (Scream's Jenna Ortega) after enduring a deadly high school shooting, highlighting the bonds between survivors of shared trauma. Maddie Ziegler, Niles Fitch, Will Ropp and Lumi Pollack round out the young cast, while Julie Bowen and John Ortiz provide the parents' perspectives on the ever-present issue of mass shootings and gun violence.

Says Park, "The movie has a trigger warning for a reason: It could be triggering for people who've been through something like this. I think that's important to know that, but at the same time, I think the movie is very hopeful. Hopefully it's therapeutic and healing for people who have unfortunately been through something like this. That was the reason I wanted to make it in the first place."

Here, Park tells PEOPLE about The Fallout, coping with tragedy, and her years-long friendship with fellow Secret Life of the American Teenager costar Woodley.

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PEOPLE: What made you want to tackle this subject matter? Did you have any experience or know somebody who did, or did you consult any real-life survivors?

MEGAN PARK: I did consult real-life survivors and their families. I am very fortunate that I've never been through something like this. I didn't pull from any one specific person or event; unfortunately, there's many that have happened, and I just think I truthfully was really frustrated and I couldn't stop thinking about what it must be like to be a high school student right now, specifically in America. I grew up in a different time. I grew up in Canada and I didn't feel this kind of threat going to school every day. It was such an emotional decision for me to write the movie because I was so terrified as an adult, let alone I couldn't imagine what it must be like to be a teenager going to school every day.

The shooting in the film happens off camera, with characters hiding out in a bathroom as they and the audience hear what takes place. What was your approach to depicting something like this so respectfully in The Fallout?

I always knew that I didn't want to show any violence. I didn't want to glorify the shooter — there was no need for that. Unfortunately, we've seen that. We're all too familiar with that, and I don't think it's helpful. I think it's actually very damaging.

It was a really important thing to get right, because I didn't want it to be triggering, but at the same time, you had to understand how traumatic that moment is to understand Vada's whole journey throughout the movie. Not only did we spend the most time talking about that scene, but the most time in the edit and the most time in the sound design, everything, because it was really tricky and really important to navigate that scene in the appropriate way and to get it right.

Obviously it wasn't as scary [on set for the actors]. We didn't have any gun sounds playing or anything like that. A lot of that was just the actors doing a really great job at creating a situation that wasn't actually happening. It was a heavy experience for everybody involved. Nobody wants to act out a scene like that, it's so awful, but we really tried to handle it in the most delicate, appropriate way we could.

Therapy is a major component in the story. Do you have any experience of going to a therapist and would you recommend it to others?

I'm a huge advocate for therapy. I hope it can become more accessible to everybody at some point. It's a wonderful resource and I highly recommend it. I think any kind of self-discovery and self-reflection is really important.

The score is done by Grammy winner Finneas O'Connell (his first film score), and there are songs from sisters Lennon Stella and Maisy Stella. How did the soundtrack add to the project?

That was an important element to me. Finneas was an incredible honor. He's a genius. He read the script, and he just really responded to it. We talked a lot about the story and it was the first film he had ever scored and very humbly, he was like, 'I've never done this before. I hope I can do it well.' And I was like, 'I think you're gonna nail it. I'm not worried at all.' It was really easy process working with him. I think he delivered such a unique, refreshing soundtrack.

What was it like working with Jenna Ortega?

She's having a huge moment, and it's so well-deserved. I hope she does whatever she wants to do because she's capable of it. She is somebody who could care less about any of the glamor, any of the other kinds of this weird side of this industry. She's just in it because she's an artist and she loves it so much. She's so down to earth and so talented. I cannot believe she was only 17 years old when she did this movie. She's just an old soul and it was just an honor. I couldn't be happier for her.

Courtesy of HBO

Shailene Woodley has a part in the film. How have you two remained close over the years since Secret Life of the American Teenager ended in 2013?

We were very, very close friends. There was never even any kind of like, 'Okay, the show's over!' and then I see her again 10 years later. I mean, I spent more time with Shai for more years than I did with my actual high school friends, so she feels like another high school friend to me in so many ways. We've always remained very close and she has been such a supporter of me as an artist. She read the script just as a friend and she was like, 'Oh my God, can I come play the therapist?' She was like, 'I wanna be a part of it and work with you as a director.' She brought flowers to set for me and left them in my trailer, and she was just so kind to all the actors and really supportive. She's just been such a great friend to me over the years.

It was so fun. We have to get into our serious mode, though, because we're so used to just being total idiots around each other. But we were able to pull together and be professional for one day!

Kevin Mazur/WireImage Shailene Woodley and Megan Park in 2009

Did you two share any teen-drama acting tips to the young cast?

They didn't need our help! They're way cooler and way more talented than we ever were at that age. Shai was so sweet with Jenna. A couple days before filming, she texted me and wanted Jenna's number so she could reach out ahead of time. We both really understand what it's like to be a young actor and how vulnerable it can be and how difficult it can be to navigate. I think we're both really sensitive to creating an environment that feels really safe for actors. I remember after we filmed the first take of Jenna on the therapy scene, Shai came over to the monitor and was like, 'Jenna is so amazing. She's such a star.'

But they didn't need our advice, they're just incredibly talented. We were just excited to watch them be amazing.

The Fallout is now streaming on HBO Max.