Carlton Cuse talks with THR about the descent of Norman Bates and his plan for the future of the A&E series.

[Warning: This story contains spoilers from the season-three finale of A&E's Bates Motel.]

The third season of Bates Motel wrapped Monday with one of the A&E drama's biggest shockers to date.

As Norman (Freddie Highmore) and Bradley (Nicola Peltz) raced away from White Pine Bay, Norman fought to keep the fictional version of Norma (Vera Farmiga) living inside his head quelled. Unfortunately for Bradley, Norman lost out to his own mind, and fully embraced becoming Norma in order to execute one of the bloodiest deaths we’ve seen on the series to date.

THR caught up with Bates Motel co-showrunner Carlton Cuse to get his take on the shocking death, taking Norman to that next level and what season four — which hasn't yet been announced — might look like.

Was the plan to always bring Bradley back just to kill her?

[Co-showrunner] Kerry Ehrin and I always planned to bring her back. Our schedule of using her was interrupted because she went off to star in the Transformers movie with Mark Wahlberg, and we really did want to give her that opportunity. At the same time, we didn’t feel like our story with her was finished. The more we talked about the evolution of the story, the more it felt like the end of the season was this big turning point for Norman, and Norman losing the ability to discern when he was in one personality or the other. We also wanted there to be a seismic event. Bradley was the perfect person to catalyze that step-up in behavior because she was the first woman besides his mother that Norman had deep feelings for. Bradley sort of felt the same way. So when she puts Norman in this incredibly difficult emotional situation where she wants him to run away with her, that sort of fries his circuitry.

Was it important to not showcase Norman as an actual killer yet?

We felt it was really important, that decision to not graphically show Norman creating the murder. In his mind, it’s his mother doing the crime, so it felt really appropriate to figure out how to best illustrate that in the storytelling. We didn’t want to show Norman committing a crime. We felt like by doing that in some ways we were preserving the audience’s empathy for the character. There still is a really good Norman inside the same body as the bad Norman. We wanted to be sure that was dramatically illustrated.

Real Norma and in-Norman’s-head Norma became hard to discern for audiences toward the end. Was that sort of the point?

We wanted to put the viewer in Norman’s head, so Norman therefore becomes an unreliable narrator. When Bradley arrived at the end of episode eight, we wanted the audience to not be sure if she was really there or if that was Norman imagining her. With the relationship with his mother, one of the interesting devices we feel we have before us is this idea that Norman is beginning to be seeing different incarnations of Norma. For him it is increasingly difficult, if not impossible, to tell which ones are real and which ones are figments of his personality. We really wanted to be able to show and tell that from inside of Norman’s head.

How difficult was it to toe the line when it came to exploring Norma's and Norman’s sexual tension?

I’m not sure that’s something we’ve seen a ton of on television. But you have a mother and son who have as close a relationship as possible, and as Norman matures from a boy into a man in this show, he is full of hormones like most teenage boys are, and those have to be directed somewhere. And the strongest, most significant female relationship he has is with his mother. So these feelings get misdirected. I think we try to walk the line and be true to the take of our character from Psycho, but not get too over the top with it. It’s just a component of Norman’s psychology. It’s interesting to explore.

Emma’s [Olivia Cooke] health was a big plot point this season. Was there ever any thought about killing that character instead?

We felt that her story of cystic fibrosis couldn’t be static and we wanted to have her make a difficult medical choice. In this case, it’s to have a lung transplant, which is potentially helpful, but there’s also a lot of risk involved. Lung transplants are particularly difficult, they’re not always successful. It was a good opportunity to take the character to another place. She has a very different perception of life, because her timeline is not the same as the rest of them. She doesn’t know whether she’s going to make it another six months; that’s a very different place to live in. So we really wanted to put Emma in a position where we would find out is it possible for her to get better or not. There’s a sense of hope, but a hope that is still tentative.

At this point is there actual hope for Norman to come back or is this the beginning of the end?

I think it would be a mistake for me to answer that question. We certainly don’t want the audience to ever give up hope. We think of Bates Motel as a wonderful tragedy. Tragedy is a great storytelling form, and as an audience you’re hoping against hope that a character escapes an inevitable outcome. Leo and Kate are on the Titanic, and you went into that movie hoping desperately that they’re not going down with the ship. We want the audience to have a lot of hope for Norma and Norman.

We left the season with Norman and fictional Norma watching the water, talking about always being together. If that were to have been the series finale are you happy with it as a closing scene?

There’s no intention of that being the end of the series. It’s not. If that was, no, I would not be OK with that — that’s not the end of our story.

Do you have an idea of what that final scene will be?

Absolutely and I’m sure it will evolve over time, as all things do creatively while we figure out the details of the remaining 20 episodes. The very end will be made richer and better as a result of the creative journey that leads us there, but do we have a specific idea of where we’re going? Yes we do.

What did you think of the Bates Motel finale? Sound off below.

Twitter: @amber_dowling