“9-1-1: Lone Star” boss on 'profound loss' of Tommy at the firehouse and 'big' Judd episode coming

Gina Torres' EMT character steps away to battle breast cancer as Jim Parrack's firefighter's woes bubble to the surface, says co-showrunner Rashad Raisani.

The 126 has a huge void to fill.

Monday's 9-1-1: Lone Star ended with Tommy (Gina Torres) stepping away from her job as EMT captain as she battles breast cancer, putting Nancy (Brianna Baker) in charge of her department.

"Nancy is going to have to step up and lead," co-showrunner and executive producer Rashad Raisani tells Entertainment Weekly. "She always has thought of herself as kind of the little sister when it came to Tommy, or even Tommy as a surrogate mother, and now her mom is sick — just like her childhood mother got sick," he continues of Baker's character, who lost her mom to cancer. "Nancy's going to have to now grow into her adulthood and her leadership with the person that she leans on the most gone. We just thought that would be a great way to send us on our final journey for the series."

Related: Tommy's 9-1-1: Lone Star cancer story was former star Sierra McClain's idea: 'It will affect everybody'

Tommy's absence from the firehouse will be a "profound loss" for all at the 126 — "she is sort of the spiritual beating heart of that firehouse," says Raisani — but particularly for Judd (Jim Parrack), who has been quietly struggling without his wife, Grace (Sierra McClain), who is off working with Mercy Ships. (A change in the show's original plan, written in after McClain left the show ahead of season 5.)

On tonight's season 5, episode 7, Judd was seen drinking off to the side on his own at TK's birthday party, perhaps an indication of what's to come for the firefighter. "We've been putting little clues in some of the scenes with Judd that will come out," confirms Raisani. "There a fuse that's been quietly lit in him, but this is sort of the final thing that falls against Judd that will come to.... It'll explode into the open in episode 10, but it's there underneath."

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The Lone Star crew has had a long relationship working with Stand Up to Cancer, beginning when Owen (Rob Lowe) battled cancer in early seasons. Raisani says the organization's input has been vital to making the show's cancer stories "correct and plausible" and with "as much humanity" as possible. As Tommy's story continues, the co-showrunner says they will explore the frustrations cancer patients face dealing with insurance companies that deny coverage based on "legalese" and "technicalities."

"For about three seasons we've been wanting to do a Mr. Smith Goes to Washington episode where Owen has to stand up against some sort of injustice," Raisani says, referencing director Frank Capra's 1939 classic film starring Jimmy Stewart as an idealistic U.S. senator. "So we're going to have the whole house stand up for Tommy coming down the pike in episode 8. Her cancer battle will affect everybody."

9-1-1: Lone Star airs Mondays at 8 p.m. ET on Fox.