Director Clint Eastwood strove for an elevated sense of authenticity in The 15:17 to Paris, casting the real heroes in the thwarted terrorist attack as the stars of his drama (in theaters Friday).

Spencer Stone makes his move on an AK-47-brandishing terrorist in 'The 15:17 to Paris.'
Warner Bros. Pictures

But the drama's climactic battle featured the film's most accurate moments, according to Spencer Stone, Alek Skarlatos and Anthony Sadler.

The three friends, now 25, overwhelmed an AK-47-wielding terrorist intent on killing passengers on the high-speed train. "The train sequence is dead-on to what happened that day," Stone says.

More: Why Clint Eastwood gambled (and won) using the real heroes in '15:17 to Paris'

Earlier: Three men who thwarted terror attack to star in Clint Eastwood film

Eastwood shot the scenes on the same French train line in moving, narrow cars with passengers from the original ride — including Mark Moogalian, who was shot by Ayoub El-Khazzani (played by Ray Corasani) after he yanked a weapon away from the gunman and attempted to warn passengers. 

Alek Skarlatos, Anthony Sadler and Spencer Stone onboard 'The 15:17 to Paris.'
Keith Bernstein/Warner Bros.

Each actor wore the exact outfit they wore during the attack on Aug. 21, 2015.

"The same clothes, the same setting, the same train, the people on the train as well," says Sadler. "It got us in the mindset of that day."

Stone, crouched behind his seat as El-Khazzani entered their car, was the first to lunge, certain he was going to be shot.

"It really came down to this: We didn’t have any other options," says Stone, noting that the AK-47 pointed at him jammed. "As I was running up to him, I was expecting to get shot at any second. I sort of blacked out. ... And then it was like, 'Oh, my God. I made it.' And it was on."

Ayoub El-Khazzani (Ray Corasani) begins his terror on 'The 15:17 to Paris.'
Warner Bros. Pictures

The two men wrestled furiously as El-Khazzani pulled out a pistol, held it to Stone's head and pulled the trigger: "It clicked, but it had no ammunition in it," Stone says.

El-Khazzani grabbed box cutters, stabbed Stone in the neck and nearly severed his thumb. "The adrenaline was flowing, I didn't even feel it," says Stone.

Skarlatos and Sadler joined the pitched battle, with Skarlatos striking an unfazed El-Khazzani with the butt of the gun as Stone held him in a chokehold. 

"He was staring back at me, making eye contact — he wouldn’t even blink. That was just amazing," Skarlatos says. "(Corasani) played that perfectly. That’s exactly how it was."

El-Khazzani was subdued, allowing the bleeding Stone, a medic, to administer first aid on Moogalian's neck wound. The dialogue of their conversation to keep Moogalian alert was spot-on.

Clint Eastwood (center) didn't hesitate to cast true heroes Anthony Sadler (from left), Spencer Stone and Alek Skarlatos as themselves when he told their story in 'The 15:17 to Paris.' "But I did think about, 'What happens if these guys turn out to be three stiffs?' "
Robert Hanashiro/USA TODAY

"It was what we said to each other, word for word," says Stone. "The same amount of blood, same injuries. I completely forgot anyone was there. I had a total flashback to the real scene. It was felt like that was reality, not fiction."

Sadler, who helped tend to Moogalian, says, "I felt like I was there that day again. I couldn’t believe I was seeing what I was seeing and hearing what I was hearing,"

None of the heroes were traumatized by re-living the events over the five-day shoot.

"It's closing a chapter in our lives, immortalized in a Clint Eastwood movie," says Skarlatos. "Now, we don’t have to tell the story. We can just say, 'Watch the movie.' "