In the film, Marathon Man, what three word question does Dr. Christian Szell repeatedly ask Thomas Levy?

In Marathon Man, the movie's line "Is it safe?" was voted as the #70 movie quote by the American Film Institute (out of 100). And this is the quote that Dr. Christian Szell (Laurence Olivier) repeatedly asks Thomas "Babe" Levy (Dustin Hoffman). After Babe is abducted, Szell tortures him using a dental probe on a cavity in his tooth and repeatedly asks "Is it safe?" (to retrieve his diamonds).

In the film, a man claiming to be an operative working with Babe's brother comes to Babe and says he needs help. Before Babe knows what is happening, he's involved in a very strange situation. It is one that he is finding hard to figure out.

The situation involves a former Nazi named Szell. He is a person that seems very ominous. He originally lives in hiding in South America. But he has millions of dollars worth of diamonds in a New York safe-deposit box. When Szell's brother is killed in what can only be described as a quintessentially New York auto crash, Szell comes out of hiding to collect his diamonds.

Szell is paranoid, and with some justification. He's afraid American agents will attempt to steal his diamonds, and this is why Babe's brother has been killed. Now Szell is in New York, looking for Babe. This is the point where "Marathon Man" starts to really unfold. All anyone understands for sure is that Babe is being pursued both by Szell and by American agents.