Overlord’s big sell might be Nazi zombies, but the movies most exciting scene doesn’t feature a single undead monster.

Warning: Light spoilers for the opening scene of Overlord ahead.

In the film’s opening moments, the plane carrying our hero Private Boyce (Jovan Adepo, Fences, Mother!) gets shot down by enemy forces. Plenty of his fellow soldiers get torn to shreds by gunfire, while others burn up in explosions, die from the fall, or get picked off by Nazi soldiers on the ground. It’s a thrilling, terrifying scene that depicts the horrors of war in graphic detail. All without any zombies.

Inverse spoke to Adepo about that brutal, early scene, which he called an “intimidating” process. Pretty much everything you see actually had to happen while filming, though it was shot in a mock plane hanging 50 feet in the air and hooked up to hydraulics.

'Overlord' beginning
'Overlord' begins with a bunch of paratroopers about to drop behind enemy lines in Nazi-occupied France.

“When you see guys tumbling out of the plane and into the flames, that was actually happening,” Adepo says. “Of course, there were people at the other end at the bottom to catch them and put the fires out, but all the actors who you see in that scene did their own stunts.”

Adepo’s character exits the crashing aircraft with a nauseating tumble through the air as bullets whiz by and explosions crash all around. Again, that all really happened, just with a little movie magic.

“Everything you see me doing in that scene, I was doing in the air,” Adepo says. “I was in a harness and rigs and all that, and they animated that scene, but I was really doing that. So it was a good mix of practical with CGI.”

Despite nearly getting the spins for the sake of Overlord, Adepo confirmed that by far the most challenging moment came right after his character barely opens his parachute in time before plummeting into a lake. He almost drowns before emerging directly under his parachute.

“To get the shot we needed, I had to have lead plates in my pocket for when I hit the water,” Adepo says. “Naturally, the human body is very buoyant. I was suspended in the air, they cut the line, then I was shot into the water.”

When Adepo acts like he’s drowning it feel real, and that’s because he really was struggling to breathe.

“You’re underwater having to hold your breath to act that you’re running out of breath which in turn makes you tired,” Adepo says. “By the time we’re doing the portion where I’m swimming upward and I take that big gulp of air, it’s a realistic reaction.”

But the opening scene isn’t the only area of Overlord that strove for total realism. Its cast also engaged in their own boot camp to ready themselves for playing soldiers.

'Overlord' Boyce and Rosenfeld
Pvt. Boyce's closest friend is Dominic Applewhite's Pvt. Rosenfeld.

“It was just under a week long,” Adepo explained of their crash course. “It was more about highlighting the correct mentality of a young man who’s away at war. Much more went into becoming familiar with the weapons of that time — how to maintain and clean then, how to maneuver the weaponry.”

This being almost 80 years ago, World War II era weaponry is totally unlike anything the military uses today. “Now we have very advanced military weapons that are made of alloys and composites of plastic and metals. Back then, it was just steel and wood. It’s the thickest type of oak that you could have. That’s what the M1 Garands are made of.” For anyone that’s ever played a World War II video game, the M1 Garand is the standard issue rifle with an 8-round magazine that makes the satisfying CLING whenever the clip empties.

M1 Garand
The M1 Garand was ubiquitous in World War II.

“So training was about learning how to maneuver with those kinds of weapons, learning how to load and reload the magazines, learning how to navigate being lost in the woods,” Adepo explained. “It was more about that and creating a bond between the actors. It was a big takeaway from that that really helped us.”

The big finale for their streamlined training was one day towards the end when the cast tested out replicas of weapons from the era. “Our military advisor wanted us to know the difference in weight of each weapon, and the sounds and the rate of fire.” Overlord depicts a myriad of era-appropriate weapons.

But then there’s the era-inappropriate zombies, which transforms Overlord into a totally different kind of movie.

Overlord lurches into theaters on Friday, November 9, 2018.