It’s a tough call, but arguably one of Precious’s most harrowing scenes is the one in which the title character and her baby fall down a flight of stairs. Even director Lee Daniels finds it difficult to watch: “It gets me every time, and I put it together,†he told Patricia Cohen during a TimesTalk interview at the New York Times Arts & Leisure Weekend on Saturday. The movie’s star, Gabourey Sidibe, also onstage, had a different reaction. “I laugh inappropriately at it — sorry,†she said. “I’m laughing because I’m not falling. Some dude named Derek is falling. And he’s not holding a baby. He’s holding a baby doll.†Daniels interjected: “Shut up, Gabby.â€