And it's unconvincing--the man has to carry a crossbeam (the entire crucifix is something up to 350 pounds) about a kilometer up a hill, and take at least three hours to die; the way Cavaziel was flayed, he should have died there, and far too quickly.
Those men handling the flagellum, the officer in charge, they have some medical training; they should know when to stop--to save the best for last, so to speak.
I don't buy it.
Incidentally, the contorted position Dafoe assumes, which conforms to the illustrations on that one crucified man archeologists found, it's far more painful than that plain ole Y shape position Cavaziel assumes. He's literally too twisted to breath easily; he can only assume that position comfortably for about ten, fifteen minutes (Scorsese said about a minute and a half). The moments when Dafoe is literally trembling with pain, that wasn't acting.