Chicago Fire Boss Teases Shay's Fresh Start, a "Powerful" Fall Finale and a Big Cliff-Hanger

Paramedic Leslie Shay (Lauren German) has never had the best timing on Chicago Fire. Last season, she jumped back into a relationship with her pregnant ex-girlfriend, Clarice, just before Clarice found out she had to move away. Then, she tried to have a baby with her best friend Severide (Taylor Kinney) just before his ex-girlfriend showed up at their doorstep pregnant and claiming that the baby was his.

However, nothing could beat the turn of events in last Tuesday's episode of the NBC sophomore drama, when Shay returned to Firehouse 51 after a serious battle with depression and suicidal thoughts only to find out that the house was being closed.

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"It's like anybody who walks the edge and either elects to walk back from it or is fortunate to have a friend or a loved one kind of guide them off that edge," showrunner Matt Olmstead tells TVGuide.com. "When you get a little more sober-minded, you're thankful for what you have. As low as she went, she comes back even better than what she was before because she realizes what she almost walked away from. It's especially troubling for her because right when she's back ready to embrace 51 with this newfound appreciation, she's looking at the possibility of the house getting shut down."

The emotions will be running high on Tuesday's fall finale (10/9c, NBC) for the entire team at Firehouse 51, who will get one last shift together before Gail McLeod (Michelle Forbes) shuts firehouse's doors and reassigns the firefighters to new locations. "It's the last day of high school or it's the last day of college, or a company you've worked for for 10 years getting closed down or bought out or downsizing," Olmstead says. "We can all relate to ... the handshakes and the goodbyes and packing the boxes and this is it. It's powerful that way and it begins to reiterate what stakes are involved. Everybody in that house has to find a way to stop the house from being closed."

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But will they really be able to save the house in time? Not only does the team have "one more shot" to possibly turn things around, but Olmstead also teases that Firehouse 51 will get emotional support from a surprising source. "I think they're somewhat taken aback by the community's support of them when they realize the house is going to close down and the lengths they'll go to save it which happens in real life," Olmstead says. "It takes everybody to try and save it including the community they've been helping out."

While it remains to be seen whether Firehouse 51 will find a way to stay open, there is another big question mark going into Tuesday's fall finale: What path will Mills (Charlie Barnett) choose? After picking up an application at the Chicago Police Department training center in the Season 1 finale, Antonio (Jon Seda) informed Mills in last week's episode that he was on the fast track to becoming a cop. But will he leave behind firefighting for good? "He does make a choice in the next episode," Olmstead says. "He's put to the test essentially and he has to decide  because, keep in mind, when he decided to go for PD, it was a bit of a parachute like coming out of the fact that I have a broken relationship with Dawson here in house and to get away from my chief."

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It probably won't help that Mills caught wind of Casey (Jesse Spencer) and Dawson's (Monica Raymund) reignited romance, which the two will continue to try to keep under wraps. "They finally have this opportunity. They want to share it with people that they work with, but they realize: Why basically kick people when they're down?" Olmstead says. "Most of the people would be happy for them, but they have Mills to consider, so it's like, 'Nice working with you, Mills. Oh by the way, I'm dating Dawson now.' So they have to keep a lid on this enthusiasm they have for this relationship in light of the fact that they have to go their separate ways."

However, that may prove extra difficult when Casey's health is put into jeopardy. "There's a big cliff-hanger and it involves Casey," Olmstead teases. "It's not their relationship either. It's Casey's well-being."

Chicago Fire's fall finale airs Tuesday at 10/9c on NBC.