Perhaps the most emotionally and physically demanding sequence of “Half Man” — and given the high drama of the HBO limited series, that’s saying a lot — took less than a day to shoot. “We finished 15 minutes early,” series creator, director and star Richard Gadd tells Variety in a Making a Scene conversation presented by HBO Max.

That’s a testament to the amount of preparation that went into planning this Episode 4 showdown. In the scene, Niall (Jamie Bell) wakes up in a hospital bed to find his lifelong bête noire, Ruben (Gadd) seated, waiting to do battle. Years prior, Niall’s truthful testimony — though he’d promised to lie on the stand — had sent Ruben to prison, and now Ruben is seeking revenge. He assaults and humiliates Niall, who, since his testimony, has seen his life fall apart; Ruben’s dominance is only compounded by the fact that, since leaving prison, he’s been on the upswing and is enjoying his life. 

In writing the scene, a culmination of all the tensions between two men who’d known one another since childhood, Gadd had to hold many elements of the show’s plot in mind. “I realized as I was writing it, it felt odd if they didn’t talk about prison. It felt odd if they didn’t bring up Maura [Ruben’s ailing mother] — all these things that happened.” 

The result, in the scene, is a massive catharsis, as both men ultimately come to a true understanding of the role they play in one another’s life. Bell says that he hoped Niall would “try and tell him, ‘You have no idea how you affect people’s lives. You have no clue what you do and how you act — how it affects people, and how it’s not just something that is brief or momentary, it stays with them for life.’” Bell calls this conversation “volatile,” while Gadd calls it “an exorcism of the soul.”

Gadd is no stranger to emotional realism: His previous series, “Baby Reindeer,” plumbed the experience of a comedian struggling with emotional and physical abuse. But the extremity of this confrontation, and its drastic shift in tones, may have been even more demanding. “The anger empties out of the room into sympathy and empathy,” Gadd says. “I felt like the only way we’re going to truly buy if they make up is by giving a lot of space to their feelings in this very moment.” 

Despite this all, the scene shot rapidly and with good humor between its two actors. 

“Me and Richard laughed a lot,” Bell says. “We couldn’t stop laughing — sometimes when we shouldn’t have been.”