[This story contains spoilers for “Does One Door Close and Another One Open?,” the season eight finale of Chicago Med.]

Dr. Will Halstead (Nick Gehlfuss) has been chafing under newly profit-centered management of the Gaffney Chicago Medical Center since Jack Dayton (Sasha Roiz) took control of the hospital. The season eight finale of Chicago Med brought his frustration to a head, when Dayton insisted on going through with a surgery assisted by his OR 2.0 system, under protest by Dr. Crockett Marcel (Dominic Rains).

The routine hernia surgery goes fine — no thanks to 2.0, which shows a complication that’s not there. Halstead admits to Goodwin (S. Epatha Merkerson) that he manipulated 2.0 to produce a bad result — and protects Dr. Song (T.V. Carpio), who hacked the system — and hands in his resignation letter. “What are we going to do without you?” Goodwin asks him.

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The law of unintended consequences, however, might catch up to the rest of the staff at Med: Dayton tells Goodwin that the botched public demonstration of 2.0 has wrecked him financially, and he’ll have to sell the hospital.

The finale is Gehlfuss’ last episode as a regular on Chicago Med; he’s one of only a handful of castmembers (along with Marlyne Barrett, Merkerson and Oliver Platt) who have been with the series from the beginning. The door could still be open for a return to the show, however — as evidenced by the other surprise in the finale: After Will leaves Chicago, he boards a plane for Seattle, where he’s greeted by Natalie Manning (former series regular Torrey DeVitto) and her son, Owen. The previous episode revealed that Nick and Natalie have kept in touch since her departure at the end of season six, and now he has moved to Seattle to restart their relationship in person.

“It was really short and sweet and beautiful — exactly what it needed to be,” DeVitto, whose appearance was kept tightly under wraps, told The Hollywood Reporter. “He’s made the move to come be with her in Seattle, where she’s living now, and they kind of walk off into the sunset and you can assume they live happily ever after.”

DeVitto spoke with THR about getting the call to reprise her role and the “special closure” she got to have with Gehlfuss.

Can you tell me a little about how your return to the show came about?

I feel like I left the show on such a good note — it was just time to move on and time to go and time to grow, really. But it was always one of those things where I knew that if they asked me back, I would enjoy going back. Because, I mean, I love my cast so much. And especially, you know, Nick Gehlfuss and I had such an intense storyline together for six years. I wasn’t expecting this call at all, but when they did call me and told me what the premise of the storyline was going to be, and that I would be coming back to support Nick and his journey on his way out, it was just a no-brainer for me. I do feel like the fans never got what they wanted with Natalie and Will, and to be honest with you, Nick and I never even got the ending that we felt we deserved for our two characters. To be able to come back and give that to not just the viewers that love the show so much and really rooted for these characters, but also to give it to me and Nick, who really wanted this ending for our characters was really so beautiful. He’s like a brother to me, so to be able to come back and support him in this way was just so much fun.

What was the experience of coming back onto the set like? Did you feel like you had any rust to shake off to get back into the character? Was it was pretty easy to step in again?

She’s a character that is more like me than any other character I’ve ever played. And because Nick and I have such great chemistry as actors together, and we have such a friendship, it honestly felt like stepping into a pair of shoes that still fit perfectly. It was so great seeing the crew. When I got out of the van [after arriving on set], everybody started clapping, which I got a little flushed about [Laughs.], but it felt like coming home. It felt like coming home to somewhere I lived for so long. And it was really beautiful. It was short and sweet, and then I was out and on my way again.

When Natalie left Chicago, it was to be near family in Seattle. Either in your own head or in conversations with the writers, have you sorted out how she’s been doing the past couple of years?

I’m sure she’s been through a bit of ups and downs because she didn’t leave the hospital on good terms. She was behaving quite unethically, trying to get those trial meds for her mom and her mom’s heart condition, and she got fired from a hospital. I’m sure she took some downtime and really reassessed her life and what she wanted to do. Now, I’m sure she’s kind of settled into Seattle and just living her life with her son, working at another hospital out there. Now having Halstead out there, it’s probably the icing on top of the cake for her.

It sounds like this is kind of closure for both of you and not an opportunity to reopen her tenure in Chicago.

I feel like there’s always, like, a chance — they can make whatever happen on this show. But from my point of view right now, it was the perfect closure that I felt like I never got with the character and that Nick and I never got with our characters together. It’s a really special closure.

If I’m not mistaken, this was the longest role you’ve played in your career to this point. What did that experience mean to you, in terms of the day-to-day work or growth as an actor?

This is the longest role I’ve played like as a series regular. But I was on Pretty Little Liars all seven seasons. So that, technically, is the longest role I ever played. But being on a show as a series regular for six seasons, there are a couple feelings you get. You can’t not feel grateful — to even have [a show get ordered], it’s like the luck of the draw sometimes. And then to have a show that actually gets picked up for a second season — people’s attention spans are so short, people don’t allow things to breathe and grow. It’s like, if you don’t like it automatically, it’s out. That’s really scary as an actor, because if you look at some of the best shows from the past, some of those first seasons weren’t that great. You kind of had to live with the characters and get to know it better to really appreciate it. To be on a show for six years and to love the character the way I did, and to get to know her the way I did, and to love my castmates the way I did, was really an experience I will absolutely never forget. I’m so, so, so grateful for it. It’s also very exhausting working 10 months out of the year, especially in the cold in Chicago. It can be a little tiring. But then by the time you get the hiatus, it’s like you forget all of that, and you just remember the good moments. But it can be hard sometimes, for sure. It’s a multifaceted experience.