Watch Bear Grylls Guide Rob Riggle through Treacherous Bowline Repelling in this EXCLUSIVE Clip from ‘Running Wild: The Challenge’

by Jon D. B.

“That’s one way we die,” Riggle quips as Bear Grylls corrects his bowline knot hundreds of feet above a Sierra Nevada desert gorge.

Rob Riggle‘s never out of his depth when it comes to comedy. But repelling using a bowline knot he’s tying himself? That’s a whole different ballgame. Life and death stakes are nothing new to the marine-turned-actor, however. Serving deployments to Liberia, Kosovo, Albania and Afghanistan, Riggle retired from the Marie Corps with the rank of lieutenant colonel in 2013.

In short: Riggle’s up for the challenge. And the season finale of National Geographic’s Running Wild with Bear Grylls: The Challenge puts him to it.

Out in the Great Basin Desert, Bear guides Riggle (Holey Moley, 21 Jump Street) through treacherous survival tests in preparation for another movie role. It’s high-stakes right from the start as the pair begin by rappelling via helicopter to head west. There, Rob is taught to tie his own bowline to traverse down an incredible, deep desert gorge.

“I did my best bowline,” Riggle tells the Running Wild crew ahead of their descent. “It’s really cool that Bear’s trusting me, and letting me take the reins on some of the decision-making.”

Riggle’s “repelled a couple of times” before, he reveals. “But never this high. And never this much heat. And never when I had to tie the knot. So, a lot of firsts today,” he smiles. And make no mistake, it is high:

The height and sheer drop-off of the gorge takes even Bear Grylls by surprise once he begins his descent. “Yeah, that’s a long way down,” the British Special Forces vet laughs as he views their path amid repelling.

But trouble strikes when Rob must get over and under a cliffside tree. He slips with an audible shout, and Bear goes on the defensive. It’s an exciting episode, to be sure, one worthy of the finale for the first season entitled The Challenge.

Two Highly-Trained Vets, One Mission: Bear Grylls & Rob Riggle Take on the Great Basin Desert

Once down into the canyon floor, Bear teaches Rob crucial river-crossing skills, food foraging tactics, and survivalist sheltering skills. But Riggle’s biggest challenge will be evading being spotted by his host in making it to their extraction point. If he fails, then he must face his biggest fear: skydiving.

Sierra Nevada Desert Gorge – Rob Riggle (L) and Bear Grylls navigate a river crossing in RUNNING WILD WITH BEAR GRYLLS: THE CHALLENGE. (Credit: National Geographic/Ben Simms)

Riggle’s episode premieres tomorrow, but Disney+ subscribers can stream all Season 7 episodes now, alongside all previous seasons. Former Guests including Channing Tatum, Brie Larson, Anthony Mackie, Dave Bautista, Cara Delevingne, Rainn Wilson, and more. This season, however, Bear kicks everything up a notch for The Challenge, putting celebrities like Simu Liu, Natalie Portman, and Riggle through some of his most dangerous excursions yet.

Each guests learns essential survival skills they’ll have to master while proving they can use each in high-stress situations. And as Bear told us in our exclusive interview ahead of the season, this set of guests truly went above-and-beyond in defying all expectations.

Be sure to catch the finale of The Challenge, “Rob Riggle in the Great Basin Desert,” as it premieres this Monday, August 22 and 10/9c on National Geographic.