'The Flash' Boss Breaks Down Barry's Heartbreaking Choice

[Warning: this story contains spoilers from Tuesday's episode of The Flash, "The Reverse-Flash Returns."]

The second time was not the charm for Barry (Grant Gustin) on The Flash.

When the Reverse-Flash (Matt Letscher) returned to Central City (from an earlier time, before he killed Barry's mom), Barry once again had the chance to prevent his mother's murder by keeping Eobard Thawne locked up in the pipeline prison. But when he realized that by doing so, he was disrupting the timeline and causing Cisco (Carlos Valdes) to die in his mother's place, Barry had to make an impossible decision. He ended up sending the Reverse-Flash back home, restoring the timeline and saving Cisco's life ... sealing his own mother's demise in the process, for the second time.

The Hollywood Reporter spoke with The Flash executive producer Andrew Kreisberg about Barry's heartbreaking choice to sacrifice his mother for the second time, how he'll be dealing with the repercussions of his decision moving forward and more.

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Why did you bring back an earlier version of the Reverse-Flash that hasn't killed Barry's mom yet? That was a surprising twist.

We really wanted to have Matt back because we loved him so much last season. We wanted to do something special. It's very easy around this time of year to tread water and have episodes that don't really have any import until things get going again, and we didn't really want to do that. Having Barry's mortal enemy back would be fodder for an amazing episode. The reason we had him come back from an earlier point in his life is that it makes things completely different. This version of Eobard Thawne hasn't experienced the events of season one yet. Whereas our crew, Barry included, are all still suffering the pain and heartache and sense of betrayal because they experienced all the terrible things that Thawne inside the body of Harrison Wells [Tom Cavanagh] did last year, this Thawne hasn't experienced any of that yet. It was a fun thing for our team to meet the real Thawne outside of normal continuity of time.

It was pretty intriguing to see a version of last season's big bad in a new way.

Yeah, I really loved watching Matt take on Thawne. This character sprang from the genius that is Tom Cavanagh and what Matt has done so beautifully is infuse his own performance with Tom's. You really do feel like you're watching the same person. This was the person who was inside the body of Tom Cavanagh all last season. There has never been anything quite like that on TV and I think that's so cool.

Barry learned a major lesson about disrupting the timeline and this is now the second time Barry had the chance to save his mom and chose a different outcome. What is Barry willing to sacrifice to save his mom? Does he even know?

I'm not sure. That's a really interesting question. As the hero, Barry keeps getting the holy grail placed in front of him and he keeps not taking it. To us, that's so interesting. The video that Thawne as Wells gave him at the beginning of the year where he freed his dad, he said, "You're never going to be happy." Barry has tried so hard to be happy, and whether that was with Patty or his job, he keeps not being able to be totally happy. Again, the chance to save his mother is presented to him and again, he doesn't take it. The question of what will it take to make Barry happy will still hang around and it will be answered by the end of the year.

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How is he going to be dealing with this choice to save Cisco instead of his mother moving forward?

It's only going to reinforce his desire to get Zoom. He can't get the Reverse-Flash because time won't let him. What's going to be happening in the next few episodes after this is Barry will renew his efforts to take the fight to Zoom.

A lot of what Barry has done his entire life has been motivated by saving his parents' fates. Is that always going to be his driving force, or do you envision Barry will be driven by something else in later seasons?

What's past is prologue. We're not thinking too much about seasons future. Last year was about solving his mother's murder and getting his dad out of jail. Both of those things have been solved. This year, we're dealing with Zoom and the repercussions from him having opened this singularity. I'm sure next year we'll come up with something else. But the effects of his mother's death, that's Barry's core wound. Whether it's a season-long arc or small, quiet character moments, I think Barry will always be dealing with that.

Now that Reverse-Flash has been sent home, has the timeline been affected in any way from the events of this episode or are things back to how they should be?

The lesson of this episode was that the timeline needed to be preserved. If anything, we know that the fact that there is no temporal repercussions from the events of this episode, that was actually doing the right thing.

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Some of the STAR Labs team will make their way to Earth-2 in a few episodes' time. Is there a chance that they might run into the Reverse-Flash there?

Not on Earth-2, but you can't keep a good Reverse-Flash down. (Laughs.) Matt is a friend and one of the nicest, most talented people I've ever met. I can't envision a universe where we don't see him again soon.

In addition to dealing with saving Cisco at the expense of his mother and sending the Reverse-Flash home, Patty also leaves Barry in this episode. Is this the official goodbye for that character, or will we see her again at some point in the future?

We love working with Shantel [VanSanten] and we'll always hope that we get to see her again in the future. But in the immediate future, this is her goodbye. We very consciously did not kill her and we all loved working with her and how much the audience liked her, so I wouldn't be surprised if we haven't seen the last of Patty Spivot.

How is Barry going to be dealing with their breakup?

Just like with not being able to save his mother, Barry was challenged by Wells in that video about how he can never be happy. Now that he's lost Patty, he's going to return his focus to stopping Zoom. He feels like, if he can just stop Zoom, then he can finally be happy.

Has he learned anything from his failed relationship with Patty that will help him in any future romances?

He's probably learned the value of being honest. That's what Iris has been explaining to him this whole time. There's a certain point in the relationship where he has to decide if it's worth keeping his secret or telling the person, and he can't really have a relationship with anybody who doesn't know the truth. He's definitely learned that lesson.

Now that Barry's single again, what's next for his love life?

I think if I tease it, I'd be ruining all the surprises. I'm just going to say, keep watching.

The Flash airs Tuesdays at 8 p.m. on The CW.