"The Flash's" Kreisberg & Cavanagh Unpack "Back to Normal," Race to Finale

SPOILER WARNING: The following contains spoilers for "The Flash" 2x19, "Back to Normal."

Tonight's episode of "The Flash," "Back to Normal," not only showcased Barry Allen's dramatically slowed-down existence in wake of losing his speed to Zoom, but it also marked some crucial turning points that set the table for the remainder of Season Two.

All caught up? Put your running shoes on as CBR News joins executive producer Andrew Kreisberg, producers Todd and Aaron Helbing and series star Tom Cavanagh for an in-depth press Q&A focusing on the startling ramifications of the episode, and the rocky road ahead for the season's final episode as Team Flash continues to deal with Zoom without Barry Allen's super speed.

On the dangers of Earth-2 Harrison Wells recreating the Particle Accelerator accident to help Barry regain his speed:

Andrew Kreisberg: I think the next episode is about the ethicacy [sic] of doing that. Harry thinks that between his Particle Accelerator explosion and what he learned from what the [Eobard] Thawne version of Wells did, he thinks he can contain it and just get Barry his powers back. But it's complicated and dangerous.

Everyone, including Barry, has to sort of decide if this is the right way to go, considering the craziness that ensued last time. They're sort of faced with a "damned if you do, damned if you don't," because Zoom is about to unleash a reign of terror on the city.

On whether or not Wells' plan could actually work:

Kreisberg: Well, that's part of what the next episode is about is, "Are you out of your mind?" This is insanity, and we're trusting everything on Harry's say so that it's all going to be fine. So I think that's part of what makes the next episode so exciting.

John Wesley Shipp returns as Barry's dad in the next episode. So there's a great scene that's between Barry's three fathers essentially. It's between Tom Cavanagh and John Wesley Shipp and Jesse Martin, where all three of them are sort of debating what their son should do. Not all of them have the take on it that you'd expect, and I think that's what makes for such an interesting scene.

On the most surprising response within Barry's triumvirate of papas:

Kreisberg: Probably Joe's, I think. Because just straight up, once Barry decides to do something, I don't think Joe thinks that he can be dissuaded from doing something. That's the Barry that Joe has come to know and love and respect. Given what they're up against, Joe, who's always been so protective of Barry, I think surprisingly is the one who says, "Maybe we should give this a shot."

On the return of Dr. Henry Allen:

Kreisberg: Barry reaches out to him now that he's lost his speed. He needs his dad. He needs his advice because Barry's sort of at a crossroads as far as what he should do or what he shouldn't do, because he's being presented with a monumental decision that could not only affect him and possibly kill him, it could kill everybody in S.T.A.R. Labs. It could set off another chain reaction and affect everybody in the city.

The last time they took matters into their own hands, they created this whole problem with blowing a hole in the universe and opening the breaches. So they're all of them a little bit gun-shy. Their faith in themselves and their faith in their decision-making is a little bit lost.

The effect of Episode 19 on Harry is, "Now I know what I've got to do and I'm going to fucking do it." Now he's sort of firmly on the team and firmly on "We're going to get Barry's speed back. This is the thing to do, and everybody should just listen to me." And everyone in the group is a little bit shaken and a little bit on their heels. "Maybe we should take a step back." So Barry reaches out to his dad for help and advice.

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On keeping Killer Frost around a bit longer, then letting her die at Zoom's hand:

Kreisberg: We loved what Danielle [Panabaker] did with her, so when we were designing this episode and we had Zoom kidnap Caitlin, it just seemed like a fun thing to do to be able to have the two of them together, and then to have Caitlin actually experience time with her, and gave us an opportunity to sort of deepen both characters.

But ultimately, she had to go. Like even she said, the only reason he kept her alive, the only reason he had to keep her alive, was she was a living remembrance of him caring about Caitlin.

We haven't met Caitlin's mother yet, so we got a little talk between the two women is something that will probably play out in Season Three.

Tom Cavanagh: The table read was great because they had these volleys back and forth. She'd be like "What do you think, tough guy?" The voice would change. It's Danielle talking to Danielle, but it's tremendous to watch. Then you put her in that outfit -- I remember we were up in the woods and shooting in the woods. It's raining. She's wearing a bustier, this kind of thing. The effects guys are like, "It's going to explode here, your eyeline has to be here. Then, when you bring it up, wait until you do the thing, hold it just for one second so we can get the plate so we can put the effect in..." All this kind of stuff. It was a lot, and she was phenomenal with it. She was just loving every minute. It was really, really impressive to watch.

Kreisberg: I think the credit, again as always, goes to all of these actors who take the time to very carefully delineate between the doppelgängers and just in the same way that Tom's done it and Carlos and Grant and Jesse and Candice. This was really Danielle's moment to shine, and really show the difference between them.

On revealing the full extent of Zoom's insanity:

Todd Helbing: In Episode Two, Jay basically tells them what Zoom is capable of doing, what he will do to be the fastest person alive. If you go back and look at that scene, you can see there's a spark of crazy there.

Kreisberg: The way Teddy plays it. He also has a line in the upcoming episode where he's like, "Do you have any idea how hard it was to be Jay?" So I think hiding his crazy wasn't always the easiest thing in the world for him to do.

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On Jesse and Wally inching closer to becoming fully integrated members of Team Flash:

Helbing: Yeah, Jesse is for sure -- now she's folded into the team. Caitlin is sort of missing, and with Jesse's smarts and scientific know-how she's really able to fill the shoes of Caitlin and provide the science background and specialty that the team is missing.

Then Wally's still not brought in as much as Jesse is into the team. He also is the only one that doesn't know that Barry is the Flash. So there are still a few more episodes of him being sort of how Iris was last year, and it takes a while before he gets fully caught up to what's going on.

On whether super-speed is destined for either of the two characters, regardless of their comic book counterparts' histories:

Kreisberg: I think right now the show is called "The Flash," and Barry Allen is the only Flash, and obviously there's expectations for both those characters, and whether or not they're realized is part of the fun and joy of watching the show. It will never be "Spider-Man and his Amazing Friends." It'll always be "The Flash."

On Iris' increasing awareness that maybe she and Barry are indeed meant to be together:

Kreisberg: As far as Barry and Iris are concerned, we really like the idea that the trip to Earth Two had a profound impact on everybody. It had an impact on Barry. Then when Barry told everybody what happened to him, it sort of had an impact on them. This whole season has been about Iris, whether she realizes it or not, trying to take a step forward. She really did love Eddie, and they probably would have had a life together, and a good one, if everything hadn't happened in the finale.

We couldn't just like slam them together. It would have been a disservice to Eddie's character and everything that happened between them. So we sort of left it on this sort of simmer all season long. Now she should be ready to move on, but she's starting to feel like the universe is telling her otherwise. We had that great scene with the flashback where Eddie gives her the message, where he basically tells her it's okay to move on.

On the mystery of the man in the iron mask:

Kreisberg: The answer is going to blow your mind. Honestly, the two things I'm probably most proud of this season are Harry and the identity of the man in the mask.

On the exciting race toward big developments at season's end:

Cavanagh: The fashion in which we sort of breathe with Barry as he's going through what he's going through is in my personal opinion one of the most inventive things I feel this show has done in the two seasons that I've been involved. I just think the way that that is crafted is brilliant. I think people are just going to love it -- it's something we haven't seen yet, and I think people are going to be extremely gratified.

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