Marathon Man is a 1974 paranoid thriller novel by William Goldman. In 1976 it was made into a film of the same name starring Dustin Hoffman, Laurence Olivier, and Roy Scheider and directed by John Schlesinger.
The former Nazi SS dentist at Auschwitz, Dr. Christian Szell (inspired by Josef Mengele, the last doctor in charge of Auschwitz II), now residing in Paraguay, must smuggle many diamonds out of the United States after the accidental death of his father in New York City. This involves a secret intelligence agency named "Division".
Meanwhile, at Columbia University, Thomas "Babe" Levy is a graduate student in history and an aspiring marathon runner. He is haunted by his father's suicide, provoked by the HUAC witchhunts of Senator McCarthy decades earlier, when he and his elder brother were boys. Unbeknownst to Babe, his brother works in Division.
Both the novel and the film contain a graphic depiction in which Szell tortures Babe by drilling into his teeth, without anesthetic, and repeatedly asking the question, "Is it safe?" Babe does not know what the question means, nor the interrogator's identity. In the course of torturing him so, Szell offers him anaestheic clove oil as inducement to cooperate.
Szell is also know for wearing a Xiphoid, a wrist-mounted automatic dagger, one of the first xiphoids seen in film.
The quotation Is it safe? is ranked #70 on the 100 Years...100 Movie Quotes list.