9-1-1: Lone Star boss on Grace in peril and that shocking diagnosis putting 'Owen and TK's future in question'

"Grace, no!" If you were screaming that at the screen during Tuesday's 9-1-1: Lone Star, you weren't alone.

"That was the trickiest part of the story," Lone Star co-creator and showrunner Tim Minear says of crafting the moment that Sierra McClain's 9-1-1 call center operator heads out to meet the man she believes has been harvesting women's organs. "Everything was sort of designed to earn the moment where she felt like she had no choice but to go out there by herself."

While Grace was ultimately fine (of course she was able to handle herself), we still had plenty of questions for Minear at the end of "Donors." Here, he addresses Grace's determination to head into danger, the return of Tamala Jones as Detective Washington, and the reveal that Owen's half-brother, Robert (Chad Lowe, real-life sibling of star Rob Lowe), has Huntington's disease.

ENTERTAINMENT WEEKLY: Why was Grace so willing to put herself in danger?

TIM MINEAR: If you look at the way that the episode is designed, she kind of takes things into her own hands early on in the story when she puts out a profile on the dating app. And of course, Judd's like, "That's a really bad idea. Don't put your picture on that website. Go find some professional law enforcement people who will care." So she does, and she kind of forgets that she's left that on the website. But everything is designed so that the table is set: Judd is at work. Carlos and Washington are raiding the dentist's office…. And Grace, who is like a dog with a bone, is not going to let this guy get away.

At least she tries to get help.

She's not an idiot, right? She's not like Carlos, just walking into a tunnel without calling somebody first. [laughs] I mean, she calls everybody. She calls Carlos, she tries to get ahold of Washington, and finally she calls the only other person who knows what's going on, and that's [Adam Baldwin's Detective] McGregor. And the question is, "Is this guy going to finally listen to her?" He does, but then we see that nobody has to save her — which is great to see. I loved seeing Sierra McClain doing all this, she has so many skills we actually haven't had the chance to exploit yet.

Jim Parrack as Judd on '9-1-1: Lone Star'
Jim Parrack as Judd on '9-1-1: Lone Star'

Kevin Estrada/FOX Jim Parrack as Judd on '9-1-1: Lone Star'

It was interesting to see Judd (Jim Parrack) in such protective mode at the end of the episode.

That's one of my favorite things too, where he shows up and he's just like, "Why didn't you just stay home?" But he's not mad at her, right? He's just worried about her. I mean, the way he dotes on her is so great. And also, that she keeps telling him to stop talking when he's yelling at the detective. She's like, "Judd, Judd." It's great.

This story also allowed you to bring back Tamala Jones as Detective Washington.

Oh my God, I love her. I told her that I probably wouldn't have done this story if she hadn't been available. She wasn't available to me earlier in the season, and then when we came up with this idea, I was just adamant, 'Do whatever you have to do to make the schedule work,' because she was booked on some other things. So I had her for a certain amount of days, but I was like, 'It's got to be her.'

Chad Lowe and Rob Lowe on '9-1-1: Lone Star'
Chad Lowe and Rob Lowe on '9-1-1: Lone Star'

Kevin Estrada/FOX Chad Lowe and Rob Lowe on '9-1-1: Lone Star'

And then amid all the tension, we get the news that Chad Lowe's Robert has Huntington's disease, a rare inherited disease that causes the progressive breakdown of nerve cells in the brain.

I've been wanting to bring Chad [back]. He was so great last year in "Shiftless" when Owen met his half-brother. His dynamic with Rob is really great. I love seeing them act together. I also sort of wanted to complicate Owen's life as we got into the last third of the season. And the connection that he made with his half-brother was only tentative last year, and so I wanted to explore that more. I wanted TK to meet his uncle that he didn't know he had. Owen's whole backstory is about how he lost a brother and he just found a new younger brother, and now it looks like he might lose him too. And because Huntington's is a disease that is carried by a gene that is impaired, it puts Owen and TK's future into question until they can get tested and find out whether or not they carry the gene. TK is about to really just start his life. He's about to get married, and this left hook comes out of nowhere, and we get to see how our characters deal with the possibility of incredibly bad news. I mean, that is life, right? It's a combination of the tragic and the joyful. That's life.

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

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