The four-part show, which is a spinoff from the Bafta-nominated 2021 feature film, premiered on BBC One last night (1 October), with the whole series also available on iPlayer.
In the series, Walters, 49, stars as a pastry chef called Emily, working in a high-end east London restaurant. Emily has a close, almost mother-son relationship with her younger colleague Jamie, played by Stephen McMillan, 24.
Warning: spoilers ahead for episode two of Boiling Point.
In the second episode of the drama, Jamie, who suffers from depression, self-harms severely at work.
Emily discovers him in the bathroom at the back of the restaurant, and is shown screaming when she finds him covered in blood.
Speaking to The Independent about filming the scene, Walters said: “On that particular day that we shot that scene, we [Stephen and I] purposely didn’t see each other. And we rehearsed that scene without him there.
“But Phil [Philip Barantini] being the incredible director that he is, he didn’t want us to over rehearse, so we just walked through the scene, and then he’d go, ‘Right, and when you open this door, he’s going to be there.’ So we never rehearsed it with Stephen there.
“So I never knew how he was going to look. I didn’t know what the state of the blood was going to be, the injury, what his face would look like, so when that door was finally opened in that shot, it was a genuine reaction of horror and shock, and it was devastating.”
Speaking about how respectful the cast and crew were on that day of filming, she added: “We have an incredible cast and incredible crew that were so mindful of the situation and what was going on.
“It was incredibly moving and beautiful to be there… because everyone was so mindful, it gave me and Stephen and everybody else just the ability to be able to really just play it for real.”
Walters said she found it hard to watch the scene back. “When we watched it in the edit, it is so incredibly real and it’s hard to watch, but it’s beautifully hard to watch.”
The self-harm storyline is revisited in the show, after being a key moment in the original film.
Speaking about the decision to revisit the theme, Walters said it was a “no-brainer”, adding: “We had such an amazing reaction from lots of people who self-harm, or from the family members of people who do.
“I would get messages saying, ‘Thank you so much for just that moment, it’s really helped my son open up.’ It felt almost like a duty of care to explore it again.”
Boiling Point is available in full now on BBC iPlayer.
If you are experiencing feelings of distress, or are struggling to cope, you can speak to the Samaritans, in confidence, on 116 123 (UK and ROI), email firstname.lastname@example.org, or visit the Samaritans website to find details of your nearest branch.
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