How Tom Cruise pulled off that 'Mission: Impossible 4' skyscraper climb and canceled his retirement from the blockbuster franchise

As the star of the Mission: Impossible movie series, Tom Cruise has been pulling off impossible missions — and improbable stunts — for a quarter century and counting. From the 1996 franchise-starter to the currently filming seventh and eight installments, the first of which will hit theaters in 2022, the actor's alter ego, super-agent Ethan Hunt, has traveled the globe and saved the world many times over.

But Cruise's license to thrill almost got revoked a decade ago in the fourth installment, Mission: Impossible — Ghost Protocol. Directed by Brad Bird and released in theaters on Dec. 15, 2011, the movie was widely assumed at the time to be the star's final outing. In a new interview with Yahoo Entertainment, Ghost Protocol stunt coordinator Gregg Smrz confirms that's how things went down in the original script, which features an extended climax where Ethan chases rogue nuclear strategist Kurt Hendricks (played by Michael Nyqvist) around a towering carpark.

"There was a point in the script when he's fighting Michael Nyqvist where he was supposed to get his leg broken," Smrz remembers now. "They wanted it hyper-extended at the knee, just shredded — end of career, you know? The studio was going to write him out, and Tom did not want it. He was strapping in his harness, looked at me and said, 'I ain't going nowhere.' Then he walked out on set and did his thing. We had [the leg break] all set and ready to go, and it disappeared."

Turns out that Cruise called his shot correctly. Far from becoming his last Mission: Impossible movie, Ghost Protocol relit the franchise's fuse with a mighty $210 million domestic box-office gross and a wave of ecstatic reviews. The movie also boasts a sequence that consistently ranks on or near the top of any list of the very best Mission: Impossible stunts: Ethan's nail-biting climb up the side of Dubai's world-famous Burj Khalifa, the tallest building in the world.

As stunt coordinator, Smrz — who first collaborated with Cruise on Mission: Impossible 2 — oversaw that scene and agrees that it's one for the record books. "I said to Brad, 'Do you have any idea what we're doing?'" he recalls. "'We're climbing 1,700 feet in the air, 200 feet up a building. This has never been done before, and it'll never be done again, because they're never going to allow it.' It's a work of art, and I don't think it can ever be beat as far as a climbing sequence on a building."

And as Smrz reveals, it's a stunt that very nearly didn't happen. Early on in pre-production, Paramount seemed poised to cancel Ghost Protocol outright before shooting started. "We had started prepping the building climb immediately on a studio lot, and were on the payroll for about before weeks when we heard that they were going to pull the plug. Tom went to have a meeting with [the studio] and we would know the outcome at the end of it."

Fortunately, Cruise emerged from that meeting with a greenlight, and Smrz and his team restarted preparations for pulling off the Burj Khalifa climb — a sequence that was always designed to serve as the movie's spectacular centerpiece. Initially skeptical that the building's owner would let them turn the 2,722-foot skyscraper into a movie set, the crew recreated three floors of the Burj on a soundstage in Prague. "We built an adjustable wall, slowly raised it until it was vertical and practiced for 200 hours on it with a crew of seven or eight guys. But Tom kept saying, 'I really want to climb that building.'"

Eventually, a compromise was reached: the production could shoot for one day on the exterior of the building, and the rest of the sequence would be shot on another 60-foot adjustable wall that has been constructed in the desert outside of Dubai. Once again, though, Cruise changed the course of production with a single sentence. "The first day [on the Burj] went so well that Tom said, 'We're filming the whole thing here on the real building.' We ended up doing one day of shooting over on the set, and the rest of it was on the real building."

With Cruise leading the charge, the Ghost Protocol crew worked out a deal with the building's owners that gave them full access to several floors that weren't yet in use. Smrz and his team then knocked out roughly 17 glass panels to make room for the stunt and camera cables and other rigging.

"I told them, 'We won't scratch your building; we're not going to damage anything.' As they saw that we were not destructive and really cared about their building, they started to work with us. There was this one guy I called Dr. No, because every time I'd ask if we could do something, he'd go, 'No!' at first. But towards the end, if I said, 'Hey, we need to drill another hole,' he'd say, 'Just tell me where.'"

As designed by Cruise, Bird and Smrz, the eight-minute Burj sequence has two distinct movements: Ethan's slow, deliberate climb up the side of the Burj in order to recover all-important nuclear launch codes and then his rapid descent. The upwards journey includes a gasp-inducing plunge where Hunt falls from an unsteady perch outside his target floor. Cruise performed the fall himself, dropping roughly forty feet from a height of 1,700 feet off the ground.

"That was probably the most nail-biting day of the show," Smrz says, adding that they only did a single take of Cruise's fall. "Somebody said, 'What if the cable breaks?' And I said, 'That's not an option.' We actually did the math, and there was enough time of free fall for him to text me on the way down, and for me to receive it!"

But Smrz also makes it clear that he would have overruled Cruise if he truly felt the star would be in danger. "If he wasn't an actor, Tom could have been a stuntman, and I would put anybody in anything if I didn't think it was safe for a stunt guy. I've got to be 99.9 percent sure it's going to be successful before we do it, whether it's a stunt person or an actor. So putting Tom into the harness was no different than a stunt guy. I expect the stunt to work, because we've already proven it over and over. "

Ethan's journey down the Burj starts with him running down the side of the building until he literally reaches the end of his rope. But he's the opposite of home free: He's still one floor above the rest of his team — William (Jeremy Renner), Benji (Simon Pegg) and Jane (Paula Patton) — and has to make a daring leap into the void to reach them. In order to gain the necessary momentum, Ethan runs in the opposite direction alongside the building and then power jumps into the air, swinging on the cable in a wide arc as he heads for the open window where William and Jane stand.

"When Tom swung on that rope around the building, Brad wanted him to go out farther," Smrz remembers. "I said, 'We'd have a problem: He has to come back, and I can't soften the impact on the glass. So the farther he goes out, the harder he's going to hit the glass, and he's already hitting it really hard.' Brad came from the world of animation where anything he wanted to do was possible, but I have a reputation for trying to keep everything real. I like to see when they hit the ground, that it hurts. But Brad was great to work with, because we'd always just sit down and talk and make sure we both were happy."

Ethan's cable swing also includes some shots that were filmed on the recreation of the Burj, including the moment where he unclips in mid-air and the moment where he flies at the window, hitting his head. But the scene where Renner clutches Cruise's leg high above Dubai was filmed on location. "We had Tom suspended on the real building, and then we dropped him," Smrz explains. "Jeremy and Paula were on cables, and they actually did dive out the window and caught Tom by his ankle. The actors did a fantastic job, especially because it was hot. We were working on glass, and it got up to 125 degrees."

The Burj Khalifa climb wasn't just a franchise-best stunt: It was also a personal best for Cruise, one that the actor has been trying to top ever since. "He wants to beat it," says Smrz, who hasn't worked on a Mission: Impossible movie since 2015's Rogue Nation, where Cruise awarded him the opportunity to choreograph the wild motorcycle chase of his dreams. "We took it to a whole other level, but it wasn't beating the building, you know what I mean? It was just a motorcycle chase. So they came up with that plane stunt. Tom's going to try to step it up to the next level in every movie, but he's also getting older: I used to tell him, 'Tom, you're going to end up walking like I do if you keep this up!'"

In that case, it's just as well that Cruise is better known for his running anyway. Asked about the actor's famously meme-friendly fleet feet, Smrz confirms he's the last person you want to be in a race with. "He can run 17-and-a-half miles an hour," he marvels. "In the scene where he's running away from the Burj, I had my stunt guys chasing him, and he was killing them. I said, 'Can you slow down a little?' And he started laughing and said, 'I'm not slowing down — tell them to speed up!' He's really fast and he has this odd style where he really lifts his legs high, and he's got the arms and legs pumping. Maybe that's his secret."

Reflecting on the Burj Khalifa climb a decade later, Smrz feels that it's increasingly rare for a studio to allow a movie star, and a stunt crew, the time and resources necessary to pull off a major setpiece on that level. "The big thing was that we really could have done that entire sequence on a stage and with visual effects. But Tom refuses to do that, because he wants climbing the Burj to be part of the thing that he does. He likes to do his own stuff, it's great for publicity and he enjoys it. It's always funny when somebody tells me, 'Tom's not going to do that — the studio's not going to allow it.' And I just say, 'He'll be doing it.'"

At the same time, with the tragedy on the set of Rust still fresh in everyone's minds, Smrz acknowledges that the industry is potentially facing widespread change in terms of how major action sequences are handled, especially when guns are involved. For his part, he believes that safety is always paramount even if it comes with a price tag. "I've been told [by studios], 'You and your guys are too expensive,'" Smrz says. "But at the end of every film, I always ask, 'Still think I'm too expensive?' and they go, 'No, we got what we paid for.' It's so busy out there right now ... and it has a lot to do with the experience of the person they hire. And right now, they're kind of hiring anybody, so it's a little scary.

"I don't think squibs and gunfire are going to go away," Smrz continues. "It's part of the job, and you have to be extra safe and unafraid to stand your ground. You have to be willing to get fired if you know that you're right and they want to push on anyway. On five occasions, I've started to walk off the set and never made it off because they realize how serious you are. You're willing to leave the movie, and that's what it takes if they expect us to keep it safe. I don't think it can get any safer: I mean, if they're going to make it so problematic that they'll just stop doing stuff, it'll all be cartoons."

Mission: Impossible - Ghost Protocol is currently streaming on Paramount+.