'Chicago Fire' Boss Talks Latest Death, Stella's "Unhinged" Ex and "Emotional" Finale

Chicago Fire Still - H 2015

Chicago Fire Still - H 2015

[Warning: This story contains spoilers from Tuesday's penultimate episode of Chicago Fire's fourth season, "Where the Collapse Started."]

In years past, Chicago Fire has saved its biggest blazes and most dangerous calls for the season finale. But now going into the end of its fourth season, the drama is changing up its tried and true formula.

In Tuesday's penultimate episode of the series, Firehouse 51 and several other companies had to respond to a massive building collapse. Although everyone from 51 came out safe and sound, Jimmy's (Steve R. McQueen) firefighter big brother was not so lucky.

Danny (Andy Ahrens), introduced at the top of the season, was given the green light to stay in the collapsing building longer by Chief Boden (Eamonn Walker) and was subsequently killed when Jimmy failed to break him free from fallen rubble.

Like past firehouse deaths (see: Darden, Shay), the death will have ripple effects for the rest of the season and beyond.

"Jimmy becomes convinced that Boden made the wrong call on letting his brother stay inside the building and starts to look at Boden as responsible for that," showrunner Matt Olmstead tells The Hollywood Reporter.

As the normally "saintly" chief knows all too well, "the game you play about when to get in and when to get out is no perfect science and sometimes people play real costs for it," Olmstead explains, pointing to the death of former firefighter Peter Mills' father, who worked alongside Boden way back when. "The chief has guilt about: 'Did I make the right call?' Ultimately he feels that he did."

However, Jimmy doesn't agree and his strong feelings about such will continue into season five. "He's convinced that Boden made the wrong call and then where do you go from there if you feel that your chief made the wrong call and got your brother in a really bad situation," Olmstead says. "We're going to begin to beat the drum on that storyline as we got out of the season."

This tension will not change the dynamic between Jimmy and his boss, but also with all of the employees at Firehouse 51. "Its complicated for the other characters because they have to be sensitive to him for what his brother went through and what he's going through," Olmstead says. "But there's a cap to it. At a certain point. Severide has to get involved, Brett is trying to advise him."

Olmstead continues: "But that advice is unheeded for Jimmy who is really picking up momentum at the end of the season. He thinks he's looking at a guy who made a mistake, won't admit it, and his brother paid the high price for it."

Elsewhere, the penultimate episode was more upbeat for Severide (Taylor Kinney) and Kidd (Miranda Rae Mayo), who consummated their romance after Severide's previous failed attempt way back when.

"Of course, we’ve played Severide loving them and leaving them and didn’t want to do a rehash of that storyline, but the actress is so formidable and we knew that she could go toe-to-toe with Severide," Olmstead says. "She's been through stuff as he is so there's similarities between the two characters. They're cut from the same cloth in a way, so we'll find it as we go along, but right now, we're still in the beginning stages of it. Obviously, her ex coming back in the picture kind of shortchanges whatever initial romance they're going to have this season."

Stella's ex, Grant (Guy Burnet), returned in a big way in Tuesday's episode when he left a note on her car and stopped by the firehouse to bring her lunch after he proved too erratic and undependable a husband earlier in the season. His erratic behavior will become a bigger factor going into the final episode of the season, Olmstead says.

"[He's] increasingly unhinged, a guy who was perfectly willing to be supported by her and carried by her while he's living out these rock star dreams that fizzled years ago," Olmstead says. "So now, faced with the fact that she really is leaving, he doesn’t want it to happen and he looks at Severide as the cause of that problem. … He's got nothing to lose and sees Severide and his ex cozying up and doesn’t take it well."

These two stories, as well as Dawson's continued quest to become a foster parent to Louie, will loom large over what Olmstead calls an "emotional" season four finale.

"We actually made a choice of, 'Let's go with a real touching, heartwarming ending coupled with a major threat, cliffhanger. We're doing both," Olmstead says. "You present both to the audience because the success of the show, we believe is that we're representing a good meal. We hopefully have something fun, we have stuff that’s heartwarming, we have stuff that hopefully moves people to tears and we have some real drama and so why not honor that in the finale"?

Chicago Fire airs Tuesdays at 10 p.m. on NBC.