This week’s episode of The Walking Dead, titled “Trust”, finally puts the screws on Mercer (Michael James Shaw), the normally stoic leader of The Commonwealth’s task-force. And spoilers past this point, but by episode’s end Mercer hasn’t necessarily turned against his bosses… But he is thinking about it.

“Going forward it puts him in a very dangerous position,” Shaw told Decider. “There’s a lot to be learned and calculated if he wants to move forward.”

In the hour, Mercer romances Princess (Paola Lázara), argues with his sister (Margot Bingham), and ultimately inches forward to changing sides. It’s part of the series’ endgame of course — when we talked to Shaw, the show had wrapped forever the previous day. To find out more about that, the episode, and just how much he had to work out, read on.

Decider: As we’re chatting, yesterday was the final day of filming The Walking Dead, ever… What has this ride been like for you, for this final season?

Michael James Shaw: It’s been incredible. For me personally, coming right out of Covid it was the best possible community to be welcomed into. It’s been a beautiful ride and I really enjoyed adding my two cents into this last bit of the journey. It’s an incredible family they have out here. I’m just lucky to be a part of it, even for a little bit.

If you were on set for the final day, what was the feeling like? Or if not, what was your feeling like on your last day on set?

So I wrapped on Tuesday. It’s that kinda like the rug being pulled from under you, you know? Because this has been my life for a year and a half now, and these are my friends and family. It’s sad, but it’s great to be able to sleep without an alarm clock for a little bit. Yeah, it’s bittersweet.

I wanted to ask you about the Mercer costume because you’ve been filming in the intense Atlanta weather, and wearing black clothes and full body armor. How are you not constantly passing out from heat stroke?

[Laughs] Well there’s a constant supply of fans coming from costumes and makeup trying to cool me off. It’s an interesting suit because it’s like being in a house with no insulation. Whatever the element is outside, whether it’s freezing cold or unbearably hot, you get the blunt end of that. Luckily enough we had some breaks where I could go dry off or put on my coat. That was labor of love, you know? Rocking the sherbert all year.

Sherbert! I love that. Jumping into the episode, it’s been fascinating watching the otherwise stoic Mercer actually open up. How much modulating of your performance has it taken over the course of the season to find that right level of humanity, versus being locked up all the time?

Yeah, the setup for him, and kind of the cold inscrutability… By the time we actually got to this point I was ready to open up and show a different side of him. And also step outside of the sherbet. Taking off the armor, figuratively and metaphorically, for me personally is what really allowed him to move in a different way, allowed you to see who he is when he’s just chatting with his sister. When he’s not in front of the public, who is the man there? And taking off the armor was a huge step in carving out that side of him.

And I imagine that relationship with Princess helps a lot in opening him up. What has it been like playing opposite Paola Lázaro?

Paola, she’s a dream. One of the most talented actresses I’ve ever met. She’s just a wonderful human being all around. It was super easy to be vulnerable and take a leap together. And figure out who these characters are together in our manifestation of it. We have the comic book as a reference, but it was freeing to step onto set that day we shot and just let go. And play off each other and live in that moment of intimacy. You don’t get too many moments like that in the apocalypse. So it was rewarding to have a moment of, “oh we’re not in fear of anything, we’re just kind of being with each other.” And it was a joy and a blessing to get to work with her on those sequences because she’s wonderful to work with.

What do you think it is about these two characters that work as a couple? Obviously, as you mentioned it does happen in the comic books, but is it just opposites attract? Or is there something more to it than that?

I think that’s a big part of it. I believe that Mercer, deep down in his heart of hearts, he really admires her freedom of expression and being. Ultimately, he would like to carve out that for himself. But he’s put himself in a predicament where there’s no room for that. And yeah, I think he’s really drawn to her because of that freedom.

There’s a scene about midway through the episode where you’re working out pretty heavily and Stephanie is really digging into him. How many times did you have to go through working out for that scene?

It took about three hours to shoot both sides of that. I must have done over 100 reps of each exercise. It was actually really fun and that was a strong component of where he was at that moment. The physical action was allowing him to really express what’s really going on. He couldn’t hold back from his sister at that moment, so I think the way the scene was built the writers, bravo to them for building such a great moment for us to play in. It really helped in allowing him to lower his guard and really express what he was feeling. But yeah, I got my workout in that day, for sure.

Photo: Jace Downs/AMC

We also get to see, pretty prominently in that scene, there’s all these inspirational posters of the character — but also you — hanging around the set. What’s it been like walking around and seeing those pictures? Have you gotten to take one home?

It’s really great to see your face all over the set. But it’s also a lot of pressure. I think that’s kinda where Mercer is, too. It’s like, “I represent something in this world and I uphold this standard.” In this episode you see him start to crumble under that pressure, or try to break free of that pressure. It’s a constant reminder of who you have to be, as opposed to who you are and what you want. But I have a couple posters and memorabilia stashed away. It’s a once in a lifetime moment, you know? I remember walking to set and the first time walking to the Commonwealth set and seeing the posters all around and I was like, “oh wow. That’s me.”

By the end of the episode, he hasn’t exactly turned against the Commonwealth but he’s certainly starting to be very conflicted. He’s definitely wavering. What kind of position does that put Mercer in going forward?

Going forward it puts him in a very dangerous position. There’s a lot to be learned and calculated if he wants to move forward.

As we start to enter the final run of episodes what can we expect from Mercer?

Well, in this episode he’s really starting to question who he is and who he wants to be. And I think he starts to really define that. That’s about all I can say.

This interview has been edited for clarity and length.

The Walking Dead airs Sundays at 9/8c on AMC, and streams a week early on AMC+.