In FX’s The Patient, Domhnall Gleeson plays a foodie named Sam Fortner who has a voracious appetite for killing — so he kidnaps his therapist Alan Strauss (Steve Carell) and chains him in his basement for round-the-clock analysis. It’s a recipe for disaster, and Gleeson — perhaps best known for playing General Hux in the Star Wars franchise — is a master at serving up the scares.

DEADLINE: When showrunner-writers Joel Fields and Joseph Weisberg first cast you, did they let you know how it was going to end?

GLEESON: No. The scripts were wonderful, and a lot of the conversations we had were about whether it was possible for Sam to get better, whether it was a futile wish on Sam’s part, or whether he wanted to control something in a different sort of way. Control is a big part of his life. So obviously, the ending has a lot to do with that. I didn’t know what the ending was until maybe halfway through.

DEADLINE: What was your initial reaction to the ending?

GLEESON: I loved it. I thought it was very emotional. I thought the letter that Alan wrote to his family was beautiful and showed his development as a patient. I thought it spoke so well of therapy and of what’s possible, despite the fact that it hadn’t worked in quite the way that Sam wanted. But weirdly it had worked in the way that Alan had wanted. I mean, he hadn’t wanted to die, but he wanted Sam to get better and understand more about his own nature and about his own capabilities. Alan said at the very beginning, therapy cannot work like this, if the patient has all of the power. That is not an even distribution. It’s not a real conversation. Sam misunderstood that. He had a desire for it to be different, he told himself that it could be different because it was him and he’s special. I think that’s a deeper problem that they tackled in a really responsible way. When I read it, I thought it felt really responsible and really moving. I think it’s a sign of really gifted writers.

DEADLINE: Did you wonder if viewers would accept that ending? That they would prefer a happy ending for Alan?

GLEESON: Yes, I knew that they would. I want happy endings when I want things, but if I knew I was always going to get a happy ending, then there would be no point of watching anything. And I think it’s important for a happy ending to be worth it and to make sense. You can’t just tag on a happy ending to something and say, oh look, we figured out this deus ex machina way that everything can be wonderful. I thought they gave the closest that it was going to be possible to give happiness to the Strauss family, which is what Alan wanted. He wanted to give them forgiveness. That’s what mattered to him more than anything else. Forgiveness and understanding and empathy. I thought it spoke beautifully to the need of sacrifice. But yeah, I did think some people will be angry.

DEADLINE: Why did Sam feel like Alan had to die?

GLEESON: I don’t think he felt his therapist had to die. But if you look at it from the very beginning, how could it be different? He was never going to let Alan go because he is too selfish. He wanted to keep him like a pet. He wanted to keep him as a validator. He had grown close to him. I do think a version of Sam’s respect and love was there. In a normal relationship, you are responsible to the people around you, which involved them confronting him about aspects of his behavior. Sam just isn’t able to live in the real world. He’s not built that way. He’s gone too far too often to deserve that. What else could he do? He was never gonna let him free, he wasn’t gonna hand himself in. There’s too much ego there, as well. I don’t see any other way for it to last if Alan insists that he won’t stay on indefinitely.

DEADLINE Some of the viewers who posted on our message board wanted to know what it meant for Sam to be chained up in his own basement. What do you think would happen? Would his mother leave him there forever?

GLEESON It depends. The writers are the people who would actually know best what would happen in that world, because it’s their world. In terms of the way I thought about it, I thought there were a couple things. I thought that it could be a week before he’s caught for killing his boss. Like, he’s killed too many people who are close to him without the finger being pointed in his direction. I also wondered how long he stays down there before he regrets handing the key to his mother and before he starts trying to use his own particular brand of manipulation to try to get her to free him. He will convince her that he is better. Or maybe he truly does understand that he cannot be out and about in the world and this is what he owes Alan, a lifetime in front of the TV, eating takeout while chained up. I kind of empathize with the world he was setting up for himself at the very end. I think he maybe continues to exist the way that I did during the pandemic.

DEADLINE Some viewers said the concentration camp scenes foreshadowed what would happen at the end. Do you feel like that’s a pretty good take on what happened?

GLEESON It’s an interesting point of view, but I think comparing anything to the Holocaust can be a losing battle. The Holocaust was such a unspeakable thing, with so many different aspects of an absolutely broken society and broken minds leading to that. You don’t want to cheapen the memory on the reality of the Holocaust by comparing it to random things in fiction.

DEADLINE Boy, did Sam have a crazy relationship with his mom, played by Linda Emond.

GLEESON It’s so f*cked up and dependent and … childish. They’re both really childish in different ways with this absolutely arrested sense of growth and development. That Strauss helps them move even a quarter step forward is sort of a miracle, even though the situation doesn’t allow for the truest version of therapy.

DEADLINE What was it like working with Steve?

GLEESON I laughed a lot on the job. I mean, it was high stakes every day and there were long scenes and a lot of eating. But Steve kept it really, really fresh and we tried different ways of approaching scenes. I really felt it was my job to try to keep giving as many options as possible. Steve is so exceptional, so reactive and creative at the same time. It amazed me how different a scene could feel by the end than it would at the beginning. I think it would’ve been very difficult for him to carry all that stuff because he had to contain his true emotions so often. Sam really displays everything that’s going on in his face. So I found myself with all sorts of ticks. Sam is no good at hiding what he’s feeling. I think it allows him to sleep a little bit better, but doesn’t allow the people around you to sleep.

DEADLINE: What was the journey like for you?

GLEESON: It was wonderful. It felt incredibly freeing. Everybody talks about collaboration, but so few people are genuinely collaborative. Even though everyone was masked all the time and being careful around each other and not having a lot of time together off set, it was truly collaborative. Those conversations were sometimes heated and sometimes not on the same page, but they always moved forward in the best possible way, with trust that everybody wanted to make something good. It was exhausting in the way that the best work is. Sometimes there is excess energy spent on sh*t that isn’t important, on conversations that aren’t important, on details that aren’t important. And it sucks the life out of a production, and it kills everyone involved. This was like the other end of the scale. His job could have been a nightmare because it’s heavy with long scenes and on one set, but it wasn’t. It was insanely brilliant.

DEADLINE: Are you prepared for people to come up to you and say, “You make an excellent serial killer?”

DOMHNALL GLEESON: I feel so good about it. I played a person who had done similarly awful things once before in a film called Calvary [with his father, Brendan Gleeson], but that was for half a day, and I prepared for that for like a month ahead of time. On this, I got to do that kind of prep. I got to have this guy in my world every day to show all different sides of him. He really made me laugh even though he was such an awful person, and he was trying. And so yeah, if people come up and say you’re a good serial killer, as long as they’re talking about the show, then I’m more than happy.