An avoidance play not to be avoided

Werner Karl Heisenberg said, "An expert is someone who knows some of the worst mistakes that can be made in his subject, and how to avoid them."

Did you see the play "Copenhagen," in which the playwright, Michael Frayn, claims that Heisenberg purposely derailed the German attempt to build a nuclear weapon in World War II? Was that true?

In this four-heart contract, it would be difficult to avoid a losing line of play. What should South do after West leads the spade king?