With Dept. Q now out, “I’ve really started to understand how different a show I was in compared to everyone else,” admits Chloe Pirrie, who delivers an outstanding performance as Merritt Lingard.

After all, in the Netflix drama, Merritt has been held captive in a hyperbaric chamber for four years before Detective Chief Inspector Carl Morck (Matthew Goode) begins working her cold case as part of a new department and eventually, working with Akram Salim (Alexej Manvelov) and Detective Constable Rose Dickson (Leah Byrne), finds her.

While the series from Scott Frank is based on Jussi Adler-Olsen’s books, giving Pirrie some idea of what to expect, “there was a lot of departure from the books as well, so I didn’t really know what was in store for me,” since Frank hadn’t written all the scripts yet, she tells TV Insider.

Below, Chloe Pirrie opens up about Merritt’s resiliency, her filming process, and more.

How did you prepare and get into Merritt’s mindset? Especially considering how long she was in that chamber?

Chloe Pirrie: I know. I did quite a lot of technical research around such things and spoke to compression divers, but then also read tons of stuff about solitary confinement — very sobering and quite heavy. That breakdown is interesting because not only is she kind of incarcerated, but she has no concept of why she’s there. So it’s the amount of unknowns. I feel like she’s so resilient, quite methodical in how she copes. I feel like my mind would just disintegrate within very little time. But she stays really strong and doesn’t allow her identity to be eroded as much as you’d think by what she’s going through. That was really exciting. She also doesn’t hold back her emotions and her anger and rage at her situation, which, to be able to do that, is so freeing as a woman, but also using my own accent, being really in my own voice in such a strong way — you can just try anything on that set. That was amazing to do. So, preparation was just letting it go.

Off that, what kept her fighting all that time? She didn’t give up.

I know. There’s something in her, maybe it’s the prosecutor, but it’s the dogmatic kind of, “I will figure this out.” She’s having these interactions, as well, with them. They don’t just leave her there without anything. She does get this kind of feedback and the sort of tactics they deploy to break her. Opportunities present themselves when she’s in there and she’s got nothing to lose. And that rage — I feel like that is in her, is activated so fully, and she sort of comes into herself in this weird way when she’s in that environment. She’s so confronted with everything in her life that she’s been running from that it’s weirdly — she’s not freed by being in the chamber because that’s absurd. But there is something that is freed within her.

What was that set like and how was filming?

That set was so amazing. Our incredible set designer, Grant [Montgomery], just built this incredible thing. Things could be taken out of it. There was a toilet that could be taken out, there were doors, walls that could be taken off for the camera and things like that. It was very claustrophobic but also really intimate. I imagine the set that Matthew, Alexej, Leah, and Kate [Dickie] were on required this kind of humor and this ensemble work, and then I’m on my own. But also the way that the crew responded, everyone just really zoned in and Scott creates an environment that really helps to levitate what he wants to happen on the set. That was very enabling, and I just had to get in the zone, but you can get in your own head very easily as an actor when it’s just you and the camera and one or two people. But we had an amazing team, and David [Ungaro], our DoP, and Eric [Bialas] who did a lot of a steadicam, they were all with me. When you get the opportunity to do that, it’s pretty cool.

Once she knew who had her and that it was about Harry, she says he deserved to die and she’d never apologize because of what happened to her brother (Tom Bulpett’s William). I loved that. Where did she find that strength? Was it purely rage at that point?

I think it’s also when you realize something — she’s gone through so many iterations of why, and then the fact that that’s the one… Those situations where you’ve been driven mad by something and then what it comes down to is something that, of course she remembers it, she’s buried things very deep, but I think it’s just the disbelief. Also, her last memories of these people are in childhood. It’s almost like in a way a childish response to something that is in essence is really messed up.

How did she feel about the Sam-is-Lyle (Steven Miller) reveal?

I know, that was wild. I sort of could see where things were going, but even this was another thing where the scripts were not yet with us, so I did sort of know, but I think even Steven didn’t even necessarily know where his story was going. Playing those bits was really satisfying, and also building that relationship. It’s such a great thing that later in the series we see this other part of her life and we see so much of her and her vulnerability starts to show in that relationship, which makes it all the worse. And she carries that relationship with her when she’s in the chamber and treasures it quite a lot. It’s pretty grim to process for her.

When she was leaving him in the flashback, then turned back, it was a completely different side of her.

Totally. The series is so clever because we play at the timeline; you don’t know certain things until Scott wants you to know them. And so realizing that all of those scenes earlier when she’s on the ferry before she’s taken, all of that had happened. We had to play things as they arrived towards us at that point because we didn’t know. You can’t think too far ahead, which is nice, I think, as an actor in some ways.

Justin Downing/Netflix

By the time Carl and Akram found her, how much had she still been holding out hope on being found? She thought she had some luck when the policeman shows up and then…

Oh my god, that bit, I know. I felt like she’d kind of resigned… Her body is really deteriorated at that point. I definitely felt pretty hopeless when I was shooting those scenes. It was going to a real extreme place of hopelessness. I think she’s not made peace with it, but she has some answers and the situation seems pretty untenable.

Also, it could very well have been too late by the time someone found her.

Totally. And you could feel that slipping away. That’s something that I read about a lot in solitary confinement accounts, that sense of your identity and your thoughts and just how difficult it is to hang on to those things in that type of situation. Your reality is so altered and your body is responding to that. Your mind and body are so connected that way. I feel like she was atrophying as a person.

I was impressed by how well she seemed to be doing after three months.

I was impressed. Those scenes were really weird for me because it’s a set I had not spent any time on. It’s a completely different vibe. The chamber was really cold to shoot in. [The police headquarters set], everyone’s in normal clothes, everyone’s joking. It was really strange for me. So I just ran with that. Scott is so fantastic. I seem to remember feeling quite like, “I don’t know how to do this scene,” but he just lets it be what it is and he doesn’t do sentimentality. He is very anti that. So I just embraced the direction and it was nice to shoot that and to work with Kate Dickie.

How would she say she’s doing?

I don’t know if she’s processed. It’s a really hard question to answer. You would have to go through so much rehabilitation to get to that point. You can’t even begin to get into it with most people that you encounter. So there’s, with most trauma, that dissociation and even if she’s working on that, she’s not going to get into that with this person she’s never met. That’s, again, where her toughness shows that there is a positivity and there is a kind of resilience there that she really has throughout that I loved.

Merritt goes down to Department Q — a great scene — and looks at their board on her case. What had she wanted to get out of going down there and what did she get? Was it what she needed?

I think it’s just taking it all in really, isn’t it? And I think maybe letting go of it a little bit. There’s just so much that she doesn’t yet know as well at the end. That lovely moment that me and Matthew crossed over, the only time we crossed over on set — I did work with Matthew! — but there’s so much that’s still unknown for her really. And I kind of like that because in life, things don’t get tied up and you don’t just get over something. Sometimes we have moments of clarity with the experience, but I think the audience has a sense of what’s happened and that she is processing, or they might feel like, okay, she’s getting something from that, looking at that board. But I think for her, it’s all just part of the wave of stuff arriving towards you in the wake of something like that.

Justin Downing/Netflix

How did you feel about Merritt and Carl never actually interacting?

Oh, it’s sort of perfect. We were in different worlds, and we were both going through it. It is really intense work and in different ways maybe. It was towards the end and it was just a really lovely day where we just had to block this little thing. It’s sort of a very simple moment, and I really love that it’s sort of tragic in a way that they miss each other like that, but it’s sort of beautiful.

Yeah, the audience knows how significant it is, but Merritt has no idea who he is.

Exactly. She still has her subjective point of view on everything and her memories and her processing of it. That’s Scott Frank being brilliant as he is.

How would you describe her relationship with her brother, and how do you think it’s going to change?

It’s probably a big thing that’s surfaced. Thinking about the earlier part of the series and the relationship that they have that’s so important to her that she treasures and how she guards that relationship and she’s structured this whole thing around it, that’s going to be very painful for her to process. But also she has him, he’s there, and that relationship that they have is the truest bond that she has in her life and he’s everything to her. I think that them reuniting is just such a special thing because the same relationship is there, even in that situation.

That reunion happening then is so important.

I know. It was so special doing that, really surreal because we had to shoot it in a really mental way just logistically. The camera was in a really weird position, so we had to do all this stuff that was like, me and Tom were straddling this thing. It was such a surreal, brilliant filmmaking day where you’re like, “Wow, that’s how they shot it, huh?” But it was amazing.

Would you want to return for a second season? It would be great to see what’s next for Merritt, maybe interacting with the others…

Look, I leave that to Scott. If the story needs it and it’s the right thing, of course, I would. But I think at the moment, it’s Dept. Q and it’s the department that we’re following. But Merritt’s around, she’s useful, she’s got skills, she’s got lots to offer.

How do you think she continues to heal? Does she throw herself back into work?

I don’t know. Do you want to go back to the same thing? There are so many directions she could go in in her life. I just want her to have a nice, comfortable time in some regard.

How does she trust anyone?

Yeah, those wounds are not going to heal easily. It’s an enormous thing. Her story’s not tied up at the end of the series. There’s a lot of questions about how a person like that could reemerge.

What was the most challenging scene to film? Or was it cumulative?

Oh, so many. It’s always the ones you don’t expect to be. I think maybe it’s some kind of Stockholm syndrome that I was experiencing where the chamber became easier, more comfortable for me. Obviously, I had to go to the really extreme emotional places to do it. Initially, we shot the chamber in intense, two-week blocks, almost like its own little film. But then towards the end, we had to jump in and out. I was doing flashback stuff, also, and that was really hard to do when jumping in and out and just kind of putting her back to how she was before when I myself was reaching capacity in terms of filming.

There were little challenges, but that’s why working with someone like Scott’s amazing because if you’re struggling with something, he just frees you. There are no wrong answers. He gives fantastic direction. … It’s a really safe environment to fail in and often the failures or the things that you thought were bad are often the things that work really, really well. You just are not objective when you’re in it, especially not when you’re playing somebody who’s going through as much as Merritt does.

Did you have a routine for decompressing after filming days?

I did at the beginning. I’d have candles and a bath and I’d walk my dog. That’s a being that needs you to just be yourself. But then towards the end, I was just like, like, “Nah, can’t deal with this anymore.” You kind of just want to be on set because it’s easier. So my process slightly deteriorated as it went on, but I think that’s also inevitable. There’s a lot of things you can do to physically reassure your body that it’s safe and it’s not real, and just really taking those opportunities and to go outside and get sunlight. I did actually come back with a vitamin D deficiency because I just was inside so much and then as it went on I got so tired. You’re just very much cocooning yourself.

Scotland, we have a good sense of humor in us generally, so there was always somebody ready in the crew to just laugh at something or slightly take the piss, which helps. Some of the times when we were shooting in the chamber, someone would make a joke and everyone just loses it because it’s so absurdly intense and heavy, you need to laugh.

Dept. Q, Season 1, Streaming Now, Netflix