After the Flood star on filming thrilling water sequence: 'The adrenaline was up'

But thankfully, Jo manages to save the day with the help of Jonas Armstrong's mystery character, who's laying low despite being a hero, which instantly raises questions about his link to the body in the lift.

Speaking exclusively to RadioTimes.com, Rundle said that she "hoped" she would be hurling herself into water when she signed up for the role.

"I think most people involved in this, the crew and us playing the characters, that's the reason we wanted to do it," she continued. "Because you read it and you're like 'who's making this? ITV? How do you deal with that? How do you film that?' So we were all really intrigued by how the f**k we were going to do it.

"And they really did just chuck us in. It was so fun, and fun to do something really different. And the adrenaline was up, it was exciting. So yeah, I did enjoy it."

Rundle previously said that as an actor who has "worn a lot of corsets and [done] a lot of holding babies and mooning after someone in the background", it was refreshing to be asked to take on such a physical challenge.

"To be doing the stunt and not just witnessing it was so exciting," she added. "I think it is so clever [to introduce the protagonist in that way]. This is the world. These are the stakes. Here she is. She's in the water. She's saved the baby and she's pregnant. Boom. You're in. How could you not watch that?"

As for how they filmed that scene, the cast and crew pitched up at Tees Barrage White Water Centre in Stockton-on-Tees for the week.

"It's where they train all the emergency services," said Rundle. "There's this water course and they have control of the speed and the scale of the water. They had all these big strapping six-foot lifeguards in all their emergency gear stationed along the water course who were lovely. They said, 'If you fall the water is going to take you but don't worry, we're going to save you.' Luckily, I didn't ever stack it, so they didn’t have to save me."

She added: "The water was really strong, and we were in and out of it all the time. On the last day I realised my hand was shaking because I hadn't eaten anything. I was so pumped. It wasn't a normal day at work where you do your lines and you go home. It really made the job for me."

Director Azhur Saleem also said that it was "tough" working with water.

"Everybody gets wet and it just slows everything down," he explained. "And there's so much that you can't control. You put people in water and you just don't know how it's going to go. That opening, it's just water from the River Tees and we recced it in October, and then in January and February we were like, 'It's pretty cold.' So we just didn't know what it was going to be like when the actors went in there.

"But they were great sports. I remember Sophie going in and we'd turn the rain on, and that rain is just fire hydrants, basically, and I just remember Sophie just kind of doing this [spreading her arms] and just getting completely doused and drenched, and then she would give me the thumbs up."

And as you'd expect, it took a huge amount of planning and preparation to make that scene possible.

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"We storyboarded that opening over and over again," he said. "We treated it like the writing process where we just kept refining it and really getting very specific about where to put the camera and getting right in there with the characters. That's what I wanted to do. This is a real event. This happens all the time all over the country, and so I didn't want to have kind of a glossy feeling to it, even though it's very glossy [laughs]. But not in that Hollywood CG way.

"I wanted it to be in there with the characters. That was really important for us, to also be in there with our characters and see it through their eyes... we all had our waders on, and we even had a boat with our wonderful director of photography. That's where our kit was and it meant that we could film from there. It became our floating Dolly and it allowed us to get close to our characters."

Saleem also revealed an interesting detail about the behind-the-scenes magic they worked on that scene.

"That's my favourite cut, when he [Armstrong] jumps in," said the director. "Everything above water was a road in North Manchester where we filmed, and then obviously the water is in Tees Barge, so that cut is a separation of three months and 250 miles.

"And fair play to Jonas. He did the exact same jump [in both places] and it worked. It's fantastic. And that for me is how we made it work, in the cut rather than relying on CGI."

After the Flood airs Wednesdays at 9pm on ITV1 and ITVX. Check out more of our Drama coverage or visit our TV Guide and Streaming Guide to find out what else is on.

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