Serinda Swan, Taylor Kinney Serinda Swan, Taylor Kinney

What happens in Vegas won't stay in Vegas on Chicago Fire.

Luck was on Severide's side on the most recent episode, when he met a beautiful blonde (Graceland's Serinda Swan) at a craps table in Sin City. Severide (Taylor Kinney) stole a kiss from the mysterious woman after she rolled two eights in a row, and the fireworks are just getting started.

"She follows him back to Chicago, to everybody's amazement," showrunner Matt Olmstead tells

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However, Severide's new romance isn't exactly well received by his friends at Firehouse 51, particularly in light of his recent nights out on the town in the wake of Shay's death. "It's all, 'Let's just keep the party going, and keep the action going. I'm dancing as fast as I can so I don't have to deal with this grief,'" Olmstead says. "That sends him to Vegas and they make an impetuous choice for her to come back and she does come back with him to Chicago. Is all this a manifestation of his reluctance to deal with this kind of floating grief from the loss of Shay? Is he making these choices because he just doesn't want to deal with it? Absolutely."

Severide isn't the only one struggling to cope with a loss. As viewers will come to learn, Swan's character, Brittany Baker, "went to Vegas to also escape some grief," Olmstead says. "So they are only able to look at it down the road, in retrospect, that there's a reason [they] were brought together. [They] were kind of guided to be together though [they] didn't know at the time because only through the other are they able to patch each other up."

The somber storyline was an important one for Olmstead to tell. "The story came from my brother-in-law who after 9/11 lost a lot of friends. He went to Vegas for three weeks and was just on a bender," he says. "It was too much for him as it was for a lot of people in that situation. On the fictional side here, we're playing the same angle for these characters. They can't deal with it. ... Only down the road do they look back when [both characters] finally have their feet on the ground from dealing with the grief of each one's individual loss and realize they were only able to deal with it through the other."

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When Brittany comes to the Windy City to follow Severide — and perhaps to escape her own grief — the couple will be crashing with Casey (Jesse Spencer) and Dawson (Monica Raymund), who have very different opinions about Severide's newfound happiness. "Everybody else is trying to interpret it or counsel him or figure it out. Casey's like, 'It doesn't make a difference to me. He's happy, I'm happy.' And he goes to Severide and says as much," Olmstead says. "Dawson has a different reaction, which then drives a little bit of a wedge between Casey and Dawson. It kind of shines a light on their relationship."

Not helping matters is the recent strain on Casey and Dawson's engagement due to her assignment to Firehouse 51 as a candidate. "Casey, as he admits, is a little jealous because here he is in this relationship where they have to kind of play 'Don't ask, don't tell,' and hide it from people and be covert," Olmstead says. "Then you look at two people who just met each other and now they're living together and they ran off. Why can't he do that?"

Chicago Fire airs Tuesdays at 10/9c on NBC.

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