Tracie Thoms as Karen Wilson on ‘9-1-1.’ Fox

This article contains spoilers for the “Tomorrow” episode of 9-1-1, which aired on October 24.

For six seasons of 9-1-1, Tracie Thoms has played Karen Wilson, the loving and supportive scientist wife of firefighter-paramedic Henrietta “Hen” Wilson (Aisha Hinds), with whom she shares a son named Denny (Declan Pratt). But as a recurring cast member on the ABC firefighter drama Station 19 and a series regular on the Apple TV+ true-crime drama Truth Be Told, Thoms had grown accustomed to blocking off a part of her schedule to shoot all of her scenes on 9-1-1 in a day or two.

So when 9-1-1 producers reached out to her team a few months ago to inquire about her availability for an extended shoot, the actress could tell something was different. “I was like, ‘Wait, what? They need me for 10 days? What’s happening?!’” Thoms told Observer. “This was all before I received the script. I had no idea what was happening.” 

As fate would have it, the 9-1-1 writers were ready to dig into the origin story of Hen and Karen’s relationship and their decision to raise Denny, the biological son of Hen’s ex-girlfriend, Eva (Abby Brammell)—all while putting Karen and Denny at the center of a heart-pounding, life-threatening emergency. Monday’s episode explores the lead-up to and aftermath of a massive explosion at Karen’s space lab, on the same day that she decided to bring Denny to work for a school project. “I got the script and read the beginning, and it said there was an explosion, and I was like, ‘Oh my God, I’m in the middle of a crisis situation. I’m in the middle of an emergency!’ Which is what I’ve always wanted,” Thoms admitted. “I’ve always wanted Karen to be in trouble, but I didn’t think it would actually happen.”

“I was so humbled and nervous, because it’s a big responsibility to carry this story,” she added. “I worked closely with the director, Joaquin Sedillo, to make sure we told the story in a way that really was conducive to the whole arc of who Henrietta is as a character now and the decisions she has to make, because we’ve been very much involved in her exploration and her desire to be a doctor. Karen’s been a reminder of those priorities at home, but she’s been very supportive and she’s trying to think ahead about things that Henrietta hasn’t even thought about, like [their] future in foster care.”

While Karen and Denny were both able to make it out of the building alive and reunite with an off-duty Hen, Karen soon collapses after a piece of debris lodged in her side nicks her spleen and causes her to go into cardiac arrest, leaving Hen, Chimney (Kenneth Choi) and Bobby (Peter Krause) frantically working to resuscitate her on the ambulance ride to the hospital. In the end, they’re able to save Karen, and Hen decides that she wants to keep working at the 118 instead of becoming a doctor, in order to spend more time with her family.

“At the end of last season, we got married, so when I first started to get an inkling that Karen was going to be in trouble, I was like, ‘Are they going to marry me to Hen again and then kill me off?’ … They really just put us in a position of being so close to each other and so fortified and unified as a partnership and a family unit,” Thoms said. “[This episode] really tells the story of how firefighters put themselves in harm’s way and how life is precious. It solidified a lot of things they do on the show to kill me off, so I didn’t put it past them. I just hoped that, if they were going to kill me off, they would tell me before they handed me a script.”

In a recent phone interview, Thoms spoke about the evolution of Hen and Karen’s relationship, the experience of working with Hinds and being part of her first 9-1-1-style emergency, and the most memorable scenes to shoot in both the past and present timelines of the episode.

Declan Pratt (l) as Denny and Tracie Thoms as Karen Wilson FOX

When I spoke with Aisha in March, she said that she is really learning more about Hen and Karen’s relationship on the fly, and she wishes she could have known certain information because it would have informed her choices as an actor in particular scenes. Now that you’ve uncovered that part of Hen and Karen’s backstory, and you’ve seen the evolution of their relationships with Denny, how has this episode changed how you understand Hen and Karen as characters and as a couple?

Tracie Thoms: I always knew that Eva and Denny were a big part of their relationship, because the very first scene we ever shot was us at the playground watching Denny play, and she was like, “Eva called.” And I was like, “Wait, what?!” So Eva was always this moving presence in their relationship until finally, [Karen] had to come to grips with the fact that “I had not been able to let Eva go, and I was keeping her alive.” Eva came back and was like, “I’m clean now. I’m moving away. I just wanted to say thank you, and I’m sorry to [Karen].” And [Karen] was like, “I don’t trust her, because she wreaked so much havoc on our relationship.”

I didn’t know exactly how she had done it. This episode explores how she wreaked so much havoc at the beginning of our relationship—how it went down. We had only seen the effects of it; we hadn’t seen what actually happened. As a fan of the show, and a storyteller, it was very interesting to me to see why Karen has had such a hard time with trusting Eva and trusting Henrietta around Eva, and where the seed of that mistrust started. The challenge is to not play the end of it and, on the day, to not play it with so much gravity, because I, Tracie, know [what’s going to happen] but Karen has no idea. Recalibrating that response was really challenging.

What were some of the biggest distinctions that you wanted to make between the Karen we see in the present and the one in the past?

Karen is such a lovebug now. She’s just so vulnerable, she wears her heart on her sleeve, and she doesn’t keep her love and her squishy parts to herself. But in the beginning of the relationship, that was not the case. Karen was a very type-A, focused, hard-working scientist, trying to manage her desires to go to space [and the reality that she wouldn’t be able to] because of where we were in the world at that time. She says, “They don’t let people like us go to space,” which is heartbreaking. [She’s] managing that disappointment and refocusing her efforts in the lab and learning how to love that. And by the time that she could become an astronaut, she no longer wanted to go to space, because everything that meant everything to her was her wife and son.

That whole arc is beautiful to see in the flesh. We’ve talked about how Karen was before she was with Henrietta. A couple of episodes ago, she was like, “You remember how I was when we first met. I was just work-work-work. I never got to be young. I never got to have fun. I never did that.” She got to explore that in one episode where she tried to go around and reclaim her youth, and then [she] realizes that, “You know what? It’s fine that I didn’t have that, because I now have this. And who I was then led me to have this beautiful life with Henrietta and Denny.”

Tracie Thoms (l) as Karen Wilson and Aisha Hinds as Henrietta “Hen” Wilson FOX

What did you and Aisha want to convey in the quiet moments between Hen and Karen in both the past and present timelines?

The quiet moments are really fun, because Aisha and I have known each other for 20 years, so we have a shorthand. It was interesting to explore, for Karen, the moments where she’s realizing that this woman, who she didn’t expect to be such a big part of her life, is actually cracking parts of her open that she wasn’t prepared for. Joaquin, our director, was like, “Don’t rush this. Just sit in this moment, let these wheels turn, and let her affect you. Let these decisions really seep into the cracks of who Karen is.”

People are always like, “Oh my God, how do you learn all those lines?” And I’m like, “It’s not about the lines; it’s about the moments between the lines.” The lines are a result of your thoughts and your feelings, and that’s how we work as human beings. Usually, in television, it’s about work-work-work, go-go-go, faster-faster-faster, but Joaquin gave us the time and space to really explore how these two women from different walks of life came together in a beautiful way.

What was it like to be part of a 9-1-1 emergency for the first time? Did you learn any tricks of the trade when filming those action sequences in the field?

Absolutely. I’ve always been in awe of them when I watch the show, like, “How are they doing this stuff?” Our crew and our production team are incredible, and they do a wonderful job of putting you into the action in a way that makes you feel like you’re there. There’s acting involved, but it’s so easy to do our jobs because it’s so realistic. There’s actual fire on the set. It’s very safe; we do a lot of safety measures. They talk everybody through what’s going to happen, but there’s not a lot of “acting to nothing.” I was prepared for that. And then I was like, “No, there’s actually a fire. Oh my God! This is so exciting to be in the middle of it!”

I come from an action background, and I’ve always wanted to do it. A lot of the tricks of the trade—how they create these explosions, how they can show real things—I had no idea [about]. But having seen them up close, I’m like, “Okay, they work so hard to create these experiences for the actors.” I have a whole new respect for them, and I have a whole new respect for the 118. They work really hard in those turnouts, and [seeing them] act through all that gear and say all this medical stuff, I’m just in awe of them.

What was the most difficult scene for you to film?

That’s a good question. It rarely happens, but sometimes, we’re going to shoot the end of a show first, which is challenging because we haven’t done it yet. So we shot the hospital scene at the end on a day that we weren’t expecting to shoot it, so you have to really use your imagination about what happened, even though you don’t know exactly how it’s going to go down. But once I just thought about it and connected with Aisha, it was fine.

But I guess the most technically difficult stuff was the lab with all the scientific speak. Just the actual physical nature of being in the lab and the fires, and keeping that intensity up for long periods of time was challenging. The first take was easy, but if you keep doing it over and over, and you’re like, “Oh, we’re in crisis,” and we’re screaming and running, it was physically demanding in a way that I didn’t expect.

What was your favorite scene to shoot?

The flashbacks were really fun. Their first date was really fun. “Okay, you have 20 minutes [to convince me this is a good idea],” and watching [Karen’s] façade crack a little bit and seeing how they began was really, really fun to explore.

I loved that Chim was the one who set them up!

Oh, I know. The shenanigans! [Laughs.] I love working with Kenneth as well. He always has a twinkle in his eye—I love that about him. I love that [Chim] was also doing that in their relationship—a little twinkle in his eye, setting things up behind the scenes. And we talked about it a long time ago! Like, “We met on a blind date, but we didn’t know it was a blind date.” I mentioned it, and the fact that the writers have been tracking this for all these seasons—these little lines here and there—and we get to see it play out is really exciting.

In the last couple of episodes, you had a chance to interact more with the other actors who play different members of the 118. Is there anyone else on the show that you’d like to work with more going forward?

Of course, Angela [Bassett] is just the queen and an icon, and I’d love to do more with Angela. But Peter is such a brilliant actor, and we’re all fans of him from Six Feet Under and Parenthood, but he’s such a kind soul. I would expect more people to ask me, “What’s Angela Bassett like?” But a surprising number of people ask me, “What’s Peter Krause like?” He’s extremely warm and giving as an actor and a human being as you’d hope he is, and I would love to play more with Peter. I haven’t acted with Jennifer Love Hewitt at all—she’s also an icon. They keep me away from people, and I don’t like it! [Laughs.] I want to play with everybody!

This interview has been edited and condensed for length and clarity.

Tracie Thoms On Her ‘9-1-1’ Character Being In the Middle Of An Emergency