Tom Cruise “literally will risk his life for the audience,” says Simon Pegg. 

Considering Pegg, 55, has starred as Benji Dunn opposite the actor-producer-stunt-legend in every Mission: Impossible movie since 2006’s third installment, he knows this firsthand.

“I've said, ‘You're absolutely nuts’ many times to him,” the English actor recalls to PEOPLE in the new special Mission: Impossible issue. “But he just cares that much about it.”

Starting with 1996’s original adaptation of the 1960s spy series, Cruise, 62, has upped the ante in each successive appearance as Ethan Hunt, high-flying, butt-kicking, fast-running agent for the Impossible Mission Force. He is now gearing up for his eighth, and possibly last, installment, The Final Reckoning, in theaters on May 23.

“I've been there for a lot of them,” Pegg continues of Cruise’s wild stunts.

Recalling a specific one — filming the sequence in 2011's Ghost Protocol, in which Cruise scales the outside of Dubai’s Burj Khalifa, the world’s tallest building — Pegg remembers “just leaning out of the window and seeing Tom sort of hanging there, smiling, this big s--- eating grin on his face, like, ‘I'm having the best time.’ "

As for a favorite daredevil moment, Pegg opts for the motorcycle-off-a-cliff scene in 2023’s Dead Reckoning Part One.

Writer-director Christopher McQuarrie’s cast and crew “were all up there together” to watch in awe, recalls the Shaun of the Dead star. 

“It was nail-biting, because we'd literally see [Cruise] just disappear, and then we'd have to wait to hear ‘good canopy’ [meaning his parachute opened safely] on the radio,” he says. “And so it was a kind of breath-hold moment.”

Another stunt that was, as Pegg puts it, more on the “interesting” side? The opening scene of 2015’s Rogue Nation, in which Cruise grips the outside of a military plane as it takes off. 

“That was the first time I'd seen him nervous,” Pegg says. “There were a lot of variables involved in that stunt ... a lot of things that could have gone wrong. Everything is managed to the micro detail. You know, the stunt team is amazing. Tom is obviously incredibly dedicated to making sure he's ready.”

Cruise, who exposed himself to potentially dangerous flying debris during that particular stunt, tells PEOPLE that when the plane taxied down the runway, his thought was, “Oh, maybe this wasn’t such a good idea.”

“I said, ‘But it’s too late. We’re committed. We’re shooting. The crew’s in there,’ ” recalls the Oscar nominee. “When we looked at the shot, I was like, ‘Oh, it really works in the story.’ ”

Cruise’s late mother, he adds, saw footage of that stunt and said, “‘Oh, honey, I’m so glad you didn’t fill me in on that one beforehand.’” 

In that Rogue Nation scene, and many others, it’s Pegg’s Benji who’s staring agog at Ethan’s — and Cruise’s — seemingly impossible feats. “It's fun to play the guy who is almost like a member of the audience,” says the actor. “To be the one that's kind of going, ‘This is crazy.’ ”

Mission: Impossible – The Final Reckoning is in theaters May 23. For more on the franchise, including exclusive interviews and behind-the-scenes photos, PEOPLE’s special edition is out now.

Additional reporting done by Erik Forrest Jackson.