'Slow Horses' Star Breaks Down Her Brutal Finale Showdown With Jack Lowden

Editor's note: The below interview contains major spoilers for the Slow Horses Season 6 finale.

Slow Horses has officially wrapped up its sixth season this week, with the Apple TV spy thriller's latest story leaving at least one major character's fate hanging in the balance. Yet even before the final minutes of "Judgment Day," in which River Cartwright's (Jack Lowden) choice to pursue a potential romantic future with Sid Baker (Olivia Cooke) may have just dangerously backfired, the Slow Horses have to confront arguably their deadliest threat yet. Between River's biological father, the ruthless mercenary Frank Harkness (Hugo Weaving), and the surviving member of the mysterious Russian assassin duo, Jane (MyAnna Buring), descending on Diana Taverner's (Kristin Scott Thomas) beach house, there's no telling who will make it out of the finale alive — and whether Jackson Lamb (Gary Oldman) can make just enough right moves to keep his remaining joes out of harm's way.

Before the premiere of "Judgment Day," Collider spoke with Buring — herself a self-professed fan of Slow Horses — to discuss her time on Season 6 and building the complex yet intriguing dynamic between Jane and Jim, played by Kyle Soller. Below, the actress also delves into what she improvised with Soller that actually made it into the season, why she wanted to give as good as she got in her brutally bloody finale fight with Lowden, her unexpected cameo during River and Harkness' heart-to-heart, and more.

COLLIDER: When you knew you were playing Jane, was there anything intimidating about stepping into her shoes, or were you just excited to play someone so mysterious and yet so terrifying because of how little we know?

MYANNA BURING: I know, right? I think there's always a mix of the two. There's always a bit of trepidation when you're walking into a show that's so well known and so well established, and that you're also a massive fan of. But then I was so excited because I'm such a fan of [director] Adam [Randall] and of the show in general, and I was so excited that Adam was going to be directing.

Knowing that I'd be working with Kyle [Soller] was thrilling. We'd met in one of our auditions, and knowing that he was going to be Jim was just amazing. So, it was pure joy. One of those jobs, I have to say. It was a bit of trepidation, and then the rest of it was just joy.

Did you and Kyle have conversations about any shared history between Jim and Jane? It feels like there's more between them than just professional colleagues on a shared assignment.

BURING: Good. Yeah, we definitely spoke a lot about backstory. We spoke a lot with Adam. Kyle and I, both of us just instinctively felt that, unless every character on screen has, for themselves anyway, an entire universe going on, you can have a whole universe going on and nobody picks up anything, but the only way that nobody would pick up anything is if you don't have a backstory.

Both of us felt very strongly that that just would really help us. We definitely had a really clear backstory about how Jim and Jane knew each other and for how long. It was magical because it meant that when we were on set, we could just improvise small, tiny gestures, small looks, and we would understand what they meant, and I'm delighted you picked up on it.

MyAnna Buring Praises 'Slow Horses' as a Playground for Improvisation

"You feel that all of the cast are the kind of actors who bring all those little moments."

Image via Apple TV

Is there a specific improvisational moment or something that the two of you did in rehearsal that made it into the season for fans to pick up on?

BURING: There’s one when we're sitting in the car park outside of the service station. There's a little moment in the car, and there's a touch. That was just totally improvised, just a sense that they mattered to each other. Small, small things like that, we kept putting in there.

Then I remember with Joanna Scanlan, when we sprayed her, we were placing her body, and Kyle was improvising small moments with her, with the TV, and I was improvising small moments in the kitchen. Things like that were really fun. That was Adam as a real sort of supporter of that kind of stuff, as well. He loves that. You can see he lights up like a child and gets excited about it in the same way that we did.

And then, just because it felt like it needed to matter when Jim dies, having this backstory that they had grown up together in an orphanage, and that they were each other's only kind of family — that song that she hums when she's looking at herself in the mirror, knowing that he's gone, is just a song that I found. I just wanted it to be something quite childlike, something from their youth that they would have listened to that would have been a comfort to them on really dark nights.

Then the impromptu stuff, which I think all of the cast do, actually; that's kind of what makes Slow Horses wonderful. You feel that all of the cast are the kind of actors who bring all those little moments. Joanna Scanlan’s Episode 4 “fuck me” is one of those moments that you almost can't write — or if you can, you just don't know that an actor's going to deliver it in the way that she can. I would by no means ever place myself in the same echelon as Joanna, but it's something that this show definitely encourages.

Anytime the Slow Horses get involved, things get so much messier and more complicated. As the mission devolves, what did you really want to convey about Jane's state of mind and how she starts to spiral?

BURING: A kind of unraveling. You have these agents who are out in the field, and they work on the premise that they have all the information they need, but they realize, as they get deeper and deeper into it, they don't have all the information. Not only that, they're dealing with morons — and then morons who are not morons, morons who are sort of dangerous morons.

And the straighter we played that as Jim and Jane, it would land more funny and also more sinister at the same time — that flip of the coin, which is precisely a sort of Slow Horses double-edged sword.

There are so many fun sequences that the two of you get to do this season. You're chasing after Olivia [Cooke] and Jack [Lowden] through this farm. You're in a bowling alley at one point, inside Diana Taverner’s vacation home. Is there any stunt or action sequence that really stands out in your mind as a favorite to do?

BURING: Well, actually there are two. One that I was not involved with is the fight scene between Kyle and Tom Brooke’s character [Coe]. I remember when that came together, it broke my heart because I thought it was just such a beautiful metaphor, and I love those two actors so much. So, to have them in this scene together, in a face-off, just felt really special.

For me, personally, the final fight with River, which was like, “Go for it. No holds barred.” Jack is such a good actor. He's so professional, and he's also like, “Bring it. I'm here.” Really, all you have to do is match him. But I think there's always that question of, “Can you match him? How physical can you get?” But I quite like properly going for it. I always think you're almost safer if you really go for it within a choreography, and it was great. It was really fun. I felt like emotionally, I’d had a full-on workout, as well, so that I loved to do.

It's so sloppy, too, which is what makes it so intense. They're throwing any kind of finesse out the window, and it just becomes almost feral. By that point, you're also covered in blood and dirt.

BURING: I know! And I think that's the sort of point of it, isn't it? Because there are elegant fights, but I think Slow Horses and the stunt team, what they do so brilliantly is that there is this acknowledgment that fights are messy when you're actually in it. They're not this beautiful ballet. In real life, they are really messy, and you end up using whatever tools are at your disposal, be it your teeth or nails or a water bottle.

Is Jim's death the turning point for Jane, or do you think there's another point in the season where it shifts from just being another assignment to her being determined to finish the job, no matter the cost?

BURING: I feel like there's definitely a shift when they're suddenly going after River and Sid, because then I felt this sense that the gloves are off now. Something has shifted, but there's also a weird glee for them.

There's something really exciting in that, and that's what I love about the turn; when suddenly, Jim's gone, then it becomes something else. That sort of psychotic glee seems to remain, but it has also somehow become personal, as opposed to just the game shifting.

MyAnna Buring Reveals Her Blink-and-You'll-Miss-It Cameo in the 'Slow Horses' Season 6 Finale

"I wanted to be there for Hugo and Jack, so I lay there for a whole day."

Image via Apple TV

One thing I've always loved about this show is, like you said, that blend of comedy and drama. The fight you have with Jack in the finale is happening amidst so much other action. Frank Harkness has shown up, and Jane's fighting River, and then…

BURING: She's gone.

Harkness just wraps it up in the most casual way possible. What stands out most in your recollection of filming that whole sequence?

BURING: I just love the thrill. There was no fanfare. It was just done, which I love. Like you say, it's got this kind of comic, delightful energy to it, just having that being cut short, and it delivers a surprise.

Every character, especially when you come into something like this, it's not so much about you; it's what it adds to the entire story. Every story is a symphony, and the most exciting symphonies have these surprising notes that come at you, and that note is cut short. You’re stunned, and then you move quickly on to something else, which I just think is appropriately Slow Horses. I loved doing it. I got really excited when I realized that that's what it would be.

I wanted to be there for Hugo and Jack, so I lay there for a whole day. Maybe it was an afternoon, but I lay there on the stairs covered in blood, with bullet holes, and just enjoyed watching them act — or listening to them acting, watching them out of the corner of my eye and listening to them. At some point, Adam went, “What are you doing? You don't need to be lying here anymore.” I was like, “Well, it adds to the atmosphere, doesn't it?”

That's amazing. So you're just lying there in the background when River and Harkness are having their father-and-son conversation.

BURING: Yes, lying in the background, having the time of my life. I came to it as a massive fan of the show, and I left it a massive fan of the show, just living out some wild fantasy. I got to hang out on set and watch two of my favorite actors just play scenes together. It was magic.

All six seasons of Slow Horses are available to stream on Apple TV, with Season 7 set to premiere at a date yet to be announced.