“9-1-1”'s Oliver Stark on Buck and Tommy's shocking relationship developments

Season 8, episode 6 of the ABC drama saw the star's firefighter discover new truths about his boyfriend — whom he invites to move in and then is broken up with.

Well that didn't go as expected.

Thursday night's episode of 9-1-1 began with Buck (Oliver Stark) and his boyfriend, Tommy (Lou Ferrigno Jr.), celebrating six months of dating and ended with, well, ending their relationship.

"Buck's head is definitely spinning," Stark tells Entertainment Weekly. "It's a lot, and it sends him spiraling, as Buck can do."

Here, the actor and 9-1-1 co-creator and showrunner Tim Minear break down the break down of Tommy and Buck.

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ENTERTAINMENT WEEKLY: The anniversary dinner starts out on bad footing, with Buck getting awkward after finding a woman dining next to them attractive...

OLIVER STARK: It didn't make the final cut, but when Tommy says it's fine to look, he even points out himself that "Look, that guy over there, I think he's hot." And I think that's lovely to be safe enough within a relationship to be like, "Yes, there are other attractive people in the world and that's very fine." But it is, I think, the first time for Buck that we are seeing, "Hold on, that's a woman and I'm attracted to her and I'm on a date with this man. And all those things can be true at the same time." I think it's just a part of him deepening his understanding of his newfound bisexuality.

Then Tommy unknowingly drops the bomb that he used to be engaged to Buck's ex-girlfriend Abby (season 1 star Connie Britton). Was that always the plan, that Tommy was Abby's Tommy?

TIM MINEAR: Did I have this planned out for eight years? Are you kidding? Of course not. But I almost did it last year. I remembered that Abby was coming off a bad breakup with her long-term boyfriend, which I sort of retconned into being a fiancé, whose name was Tommy. That idea just tickled me.

It doesn't tickle Buck.

STARK: It rocks his world a little bit and kind of sends him in somewhat of a spiral. We've come to know Buck as a hugely protective person — of strangers every day in his job, but even more so of the people he loves and cares about, Abby being one of those people. They're not together anymore, but she was somebody hugely important in his life. To know that Tommy really hurt her is hard for Buck to deal with. It just makes him take pause and look at Tommy slightly differently — which is unfair, but is a very Buck thing to do. Knee-jerk reactions are very much a part of his character and sometimes he just has to slow his roll and wait for a little more context.

But Buck's mood shifts quickly after a chat with Maddie (Jennifer Love Hewitt) and Josh (Bryan Safi) and he decides he wants Tommy to movie in...

STARK: In itself, thats quite a knee-jerk reaction. From zero to 100. I think that the talk with Maddie and Josh is obviously pretty instrumental. Buck is new to this lifestyle, new to understanding himself and the queer experience. And Josh being able to guide him a little bit, I think, was a really nice moment between the characters. That conversation makes Buck realize how lucky and happy he is.

Well, happy until the move-in proposal doesn't go well and Tommy breaks up with him.

STARK: It does very much come out of nowhere. I think Buck asking such a huge thing of Tommy jolts him into almost having to make this decision for himself and for Buck. To me, the scene plays that Tommy has been hurt before and is scared of being hurt again. He's very much trying to protect himself, which I hold no judgment over. And yeah, unfortunately Buck is just the casualty of that playing out.

MINEAR: I think Tommy probably went into this relationship realizing that at some point his heart would get broken, but it's just like, "How broken?" How much are you going to let somebody capture it? How broken do you want it by the end of it? It's worth it for him to have a broken heart here, because he's with Buck and it's kind of great. Tommy knows that the bloom is going to fade off the rose at some point, and that if he took Buck up on his offer to move in.... Like he says, "I know how this ends," which may be a stupid thing for Tommy or may be a wise, self-protecting thing for Tommy.

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The episode ends with Buck sharing a silent beer with Eddie (Ryan Guzman). But what happens next?

STARK: Buck is very much going to look to channel his heartbreak into positive hobbies, pretty much to an obsessive degree, which is noticed by a few people around him and presents some lighthearted and fun scenes for the cast. In typical Buck fashion, he's going to keep moving forward and find a way to cope with it. The cracks will probably start to appear, but certainly to begin with, the mask and the facade is going to be very much one of "I'm okay."

What did you think of the episode? Let us know in the comments below.

9-1-1 airs Thursdays at 8 p.m. ET on ABC.