Benny Safdie wanted to be a physicist, and he almost went to Reed College to study nuclear reactors. He’s telling me, over the droning of the diner’s Christmas soundtrack, about dark matter and the Doppler effect, cosmic rays and Carl Sagan — and about how he’d said goodbye to all that to study film. He could never have anticipated that years later, Nolan would recruit him to play Edward Teller, the theoretical physicist and father of the hydrogen bomb, in his blockbuster “Oppenheimer.”

Putting on prosthetics to argue about physics in a fully re-created Los Alamos was a special kind of immersion for Safdie, who spent weeks perfecting Teller’s Hungarian accent by listening to his speeches while riding his bike around New York. (For the movie’s later scenes, which take place 20 years after the Manhattan Project, Nolan suggested Safdie eat cheese to age up his voice.)

That wasn’t the only thing Safdie learned from Nolan. He was shocked as he observed the director’s “fluidity,” as Nolan would begin each scene with nothing set up except the lighting.

“You’d come into the room and Chris would say, ‘All right, let’s go.’ No camera. Everybody’s in makeup, and we’d just do the scene. And then it was like, let’s figure out where the cameras go,” Safdie recalls. Whereas most directors would already have the scene conceptualized, with Nolan, “it was pure openness.”

“This is a huge movie,” Safdie continues, “and he’s still operating with that level of freedom. As an actor, it made me feel awesome.”

Safdie also praises Nolan’s efficiency, and his “confidence” in moving on after just one or two takes. “It feels like such a perfect movie that the way it was made is almost a contradiction to that — because it’s so loose,” he says.