Speaking to HitFix in Los Angeles, the "Veep" actor Walsh admitted to stepping outside his wheelhouse to become a dead-serious tornado chaser for the flick, which in turn prepared him for more "action, stunt-heavy" roles.
"It's like being a 12-year-old kid," Walsh said.
"You should do 'Expendables 4,'" Sumpter urged.
"Stallone, I'm ready."
The high-winds action had huge scale on screen, but the actors had to do a lot of studio work, with blue screens and VFX in post to make it look real. Still, that didn't mean they didn't feel peril: Sumpter described that "everything you see [on screen] is there," with the help of elements like wind machines, rain machines, "real explosions" and flying debris.
"The sets were unreal," he said.
So what marks a good disaster flick and a bad one?
"'Twister' marked a bad one," Sumpter joked, breaking a light, unspeakable taboo of name-checking the movie one's own movie resembles most. He explained, though that "it was my favorite movie as a kid."
Watch the rest of the video above, for Sumpter's transparent lies about Niagra Falls, and Walsh's clear explanation on why chucking babies into wind machines is "very expensive."
"Into the Storm" is in theaters on Friday (Aug. 8).