'Chicago Fire' Boss on the Surprise Finale Hookup, That "Ambitious" Casey-Dawson Twist

"We knew we were taking a big swing, but I think that you've got to trust the fact that you're going to land on the other side of it," Matt Olmstead tells THR.
Elizabeth Morris/NBC

[Warning: Spoilers ahead for the Chicago Fire season three finale, "Spartacus."]

Dawson (Monica Raymund) appeared to get some very surprising news regarding her and Casey's future on Tuesday's Chicago Fire season three finale, but unfortunately Casey (Jesse Spencer) was nowhere to be found. In the final moments of the episode, Dawson took a pregnancy test. However, the results weren't shown, and when she went to reveal the results to Casey, he was missing and strip club employee Katia was dead.

So where do they go from here? "We're not sure. There are a couple scenarios we are actively debating in the room right now," showrunner Matt Olmstead tells The Hollywood Reporter. "But the stone that we dropped in the pond so to speak at the end of the season — the mere fact that we're in the room having a robust discussion about what those ramifications could be was a good sign that we're on to something. It's better to have a couple different possibilities, even though there are pros and cons to everything, rather than to play it safe and have the relationship fizzle out, and they go on Match.com and date other people. We knew we were taking a big swing, but I think that you've got to trust the fact that you're going to land on the other side of it. You just have to be ambitious and bold and take chances, which is what we're doing."

Although Olmstead was tight-lipped about exactly what's ahead for the two, he did open up about that other shocking development: the crossover hookup between Chicago Fire's Brett (Kara Killmer) and Chicago P.D.'s Roman (Brian Geraghty). Olmstead also talked with The Hollywood Reporter about the decision to pair Brett and Roman, why a proposed romance between Brett and Severide (Taylor Kinney) was scrapped and what else is in store for season four.

When did the idea come about to put these two people together?

We always look at each board on each show and look at potential romantic pairings. You can't do it too often because there are ramifications; people work together, things like that. Then we look at potential romantic pairings connecting the two shows, and obviously we dealt with Severide and Lindsay. We did it and continue to do it with Mouch and Platt, and we just wanted to look again at if there was anything coming up in terms of going to that possibility. We were looking at Brett. She had a relationship with Cruz, but is free right now. It's a little bit dangerous to have her date someone else that's in the house because there are ramifications to that. How will Cruz react? We've already played that Dawson's dated a couple of people in the house, so there's a sameness to that. We started looking at P.D. where we have the Roman character who had an ex-girlfriend, so then he's available. Then we were like, what would that be like? The possibility of the chemistry really jumped out at us and so that's where we wanted to go. It's a button within the finale and we'll see where it goes next season.

Why do these two gravitate towards each other?

With Brett, we wrote that Severide — when he was starting to spin out a little bit — kind of reflexively went over to her and asked her to go to Vegas. She's just not that kind of girl. So she's a little cautious when it comes to dating, having gotten out of a long-term relationship. As evidenced by her dating Cruz, she just wants a good guy. The guy she was engaged to was a bit of cad. With Roman, we've established that he really likes being in uniform, doesn't like to play the politics of Intelligence upstairs, and so they're both liberated at the moment. I think they both appreciate a good person as opposed to just looking for a roll in the hay. There's just something about what these actors bring to these roles that it made conducive to this relationship.

What kind of obstacles will they face next season?

One of them is people getting in their business, which I think both have experienced before. They don't care for it, but there are two sides to it. One of them is it's cool that they're not dating someone within their firehouse or their district, but it's still a small world. And then, as oftentimes happens in those relationships, when you start caring about somebody, you start worrying about them on their job. She's a paramedic and he's a uniform cop, and so they have to deal with that layer of concern in terms of what they do for a living, but we want to play it as a fun relationship. They're both ready for something like that in their lives. Again, we'll see how it plays, but we hope that it's going to play great.

You brought up Cruz [Joe Minoso] earlier. Is he going to find out soon? How will he react to the news?

We had explored a romance between Severide and Brett later in the season, and a couple of times we had put it up on blocks and examined what that would look like. Obviously, its easier to have a romance between two people on the same show because you get to see day-in, day-out, scene-in, scene-out conflict, romance, the whole thing — and then there are ramifications to other people who you can play. But then it started to look bad on Severide in terms of moving in on to Brett knowing that she had dated Cruz. It made Cruz look bad in terms of being the bridesmaid once again essentially, and the girl he likes jumps towards the playboy of the house. Plus it made her not look that great in terms of presenting her a certain way, and then she chucks it out the window for a fling with Severide. So we liked it initially when we were exploring the idea, but then we realized that the bill afterwards was going to be too great so we scratched that and decided to go with Roman. That protects everybody. It protects Severide because he's not being predatory towards Brett. It protects Cruz because she's at least being respectful not to date somebody within the house. She's going outside of it, and at that point, he can't ask for anything more. If he did, he'd be a chump. She's living her life. He's living his life.

Does this lead to a double date with Mouch [Fire's Christian Stole] and Platt [P.D.'s Amy Morton]?

That's so funny. That's on the board for next season. Absolutely.

Is there a theme for season four?

There are shifts within the firehouse that you're going to see at the end of this season and at the beginning of next season in terms of personnel and people having some new roles within the firehouse — within their personal lives. People get knocked out of their comfort zone a little bit and we see how they react to it.

Is there any particular new role you're excited about?

We're excited about bringing in a new candidate to the firehouse, which we're going to cast and look for. It's another opportunity to bring in new blood with the graduation of characters and the Mills character going off. It opens up a spot for a new character — a new candidate — and we're tossing around ideas right now about who that character will be. It's always cool to have a character walk in that has no idea what they're walking into. It's almost like an audience surrogate — the audience experiences what the character experiences because everything is new to them.

Chicago Fire returns for season four in November on NBC.