It's been 15 years since the movie premiered, and people are still talking about that ending to "The Mist." It's an ending that almost seems happy on the surface: The storm turns out to not be nearly as all-encompassing as it originally appeared, and the military is now swooping in to save the day. David Drayton (Thomas Jane) will not be eaten by Lovecraftian monsters after all, and the world will presumably go back to normal pretty soon. The only problem is that he just shot his child and the other survivors in his car. For the rest of his life, David will have to deal with the fact that his eight-year-old son would've been perfectly fine if he'd just waited a few more minutes.

It's a gut punch of an ending — one that shocks you to the core the first time around and makes rewatches nearly unbearable. As you watch that final scene again, you can't help but hope in vain that maybe this time David will wait a little bit longer before giving up hope altogether, but he never does. It's a frustrating ending, but an undeniably powerful one. /Film's own Eric Vespe got to talk to the cast and crew of "The Mist" about how they went about filming such a devastating, climactic scene. Every quote in this article comes from Vespe's wonderful, in-depth reporting on the movie's production.

The Car Scene

For Thomas Jane, his performance in those final few minutes was easily the most important of the film. He had to make it believable that he as David had sunk to the point where he was willing to kill the others to protect them from a worse fate, and then he had to capture the unimaginable level of regret his character feels when the mist clears up. It was an incredibly dark place Jane had to get to, and it took a lot out of him off-camera. "That was a day where I told the first AD that if he needed to find me, I'd be out in the woods," Jane said. "I spent the entire day by myself sitting on a log, waiting in-between takes."

The ending scene was split into two main set-ups: Inside the car and outside of it. The interior scene, where David had to make the choice to kill everyone, was actually the easier one for Jane. "We had three other actors and the pressure wasn't all on me and I had other people to feed off of," he explained. One of the toughest parts was filming the moment where the son, Billy (Nathan Gamble), woke up as his father was about to shoot him. In the movie, all we see is the son's reaction as he starts to realize what's about to happen. The deaths themselves happen off-screen.

"We shot a couple of takes with Billy waking up and the gun wasn't there, just as a practice and a warm-up," explained cinematographer Rohn Schmidt. "I think this was [director Frank Darabont's] idea, and then we gave the gun to Thomas. So that reaction that you get with the gun right there aiming at him, you could never have acted that. That really is surprise on his part there."

Pointing A Prop Gun At An Eight-Year-Old

It's always an extra challenge to direct a child actor in an adult horror film, and the decision to surprise young Nathan Gamble with the gun pointed at him did not seem to be made lightly. Ron Schmidt explained that Gamble's parents were "on board with that idea," and knew about it ahead of time. But for Gamble, according to Schmidt, his reaction on set was "the most absolutely true and pure reaction … I feel like his eyes dilate uncontrollably."

For Gamble, the scene was unique in how bare-bones it was. "Obviously everyone in the car, [director Frank Darabont], the camera guy, maybe one or two other people there when we were rehearsing it," he said. "I remember when we were rehearsing this particular thing, when Frank asked me to wake up, 'Slowly wake up and look at your dad and look scared, look shocked.' Tom would be holding the gun at me on the other side of the camera." It's a different approach than some of the other King adaptations have taken with their child actors; whereas Danny Lloyd didn't even know he was filming a horror movie while on-set for "The Shining," Gamble seemed to be fully aware of how dark the story of "The Mist" was getting.

Gamble recalls how shaken Thomas Jane was when the scene ended: "When they yelled 'cut,' Tom laughed afterwards because he couldn't believe how ridiculous his life was at the moment, 'I'm holding a fake gun on a child right now,'" Gamble said. "I can see his brain working. It was just like, 'Wow, in all my years, I would've never guessed that this scene I would ever shoot.'"

As Little Takes As Possible

It's the moments immediately after the shooting, when David is screaming and crying in his car, that were truly difficult for the cast and crew. Even Gamble, who was no longer on set for this part, could still hear him screaming through the walls. "I had the school room where I did school on the other side," he said, "and I could hear the screaming from him and it was pretty sad."

For producer Denise Huth, the scene was torturous. "There's something about the visual of seeing him with the gun in his mouth and he just keeps pulling the trigger and praying for a bullet that's not there. It's crushing. It's the lowest moment. And he really committed to it." They didn't take many takes of the scene due to how draining it was to film them. Sometimes, when the scene requires so much of the actor and the actor's fully embracing it, once or twice is enough.

For the final gut punch, the reveal of the mist parting and the military coming in, the crew moved to an exterior location. The beginning of the scene needed to be shot early in the morning, and because of all the mist, they had to hope the wind would be cooperative. As was the case for the rest of the movie, dealing with the mist was a total hassle, but they made it through.

Driving A Tank Through The Fog

As Schmidt put it, "After the first take, the tank driver said, 'Well, I can't see where I'm driving.'" The lack of visibility wasn't great from a safety perspective, especially since he was driving 25 miles an hour in a tank directly at the cast and crew. "What we ended up doing was lining him up where it was safe and then him driving straight back and not touching the steering at all … he just had to travel forward on faith."

With the tank, the fog, the cameras, and all the soldiers and other minor cast members in the scene, it was a lot of pressure for everyone involved. It wasn't just that Thomas Jane had to do everything perfectly; everyone else needed to be perfect as well. Director Frank Darabont also made the choice to include a crane shot, which is one of the most difficult shots to pull off. "There's so many moving parts," Jane said. "You have to be on, but so everybody else has to be on, which means that you have to be on more than once."

In the end, the shot that made it into the final cut wasn't even Jane's best performance. According to Schmidt, they went with the take where they "got lucky with the wind," the one where everything else in the shot turned out great as well.

Stephen King-Approved

It's easy to underappreciate just how much work went into this final scene, because it's the sheer weight of the plot twist that seems to stick out to me the most. Even if Jane wasn't giving the performance of his career in that final scene, the sheer enormity of what's being revealed to us is so devastating that it might've even worked with a bad actor. The way the movie makes it so easy for us to imagine how we'd feel in the same situation is what makes the ending so haunting.

Even when only the script was available, the twist was good enough for King to love and support it. Back before the movie was released in theaters, King told fans that the movie has "the most shocking ending ever and there should be a law passed stating that anybody who reveals the last five minutes of this film should be hung from their neck until dead."

But it's that extra effort made by the cast and crew — the standout performances, the inspired direction — that raises "The Mist" from a strong film to a modern classic. "[Jane's] performance was so strong," producer Denise Huth said. "He was that man who had been completely destroyed by the events of the last couple of days. Nothing was going to put him back together." For the crew, just as much as the viewers, "The Mist" has an ending that will stick with you forever.

Read this next: The Saddest Character Deaths In Horror History

The post What It Was Like to Film The Mist's Legendarily Dark Ending [Exclusive] appeared first on /Film.