The Lady or The Tiger?

"Her right arm lay on the cushioned parapet before her. She raised her hand, and made a slight, quick movement toward the right. No one but her lover saw her. Every eye but his was fixed on the man in the arena.

He turned, and with a firm and rapid step he walked across the empty space. Every heart stopped beating, every breath was held, every eye was fixed immovably upon that man. Without the slightest hesitation, he went to the door on the right, and opened it.

Now, the point of the story is this: Did the tiger come out of that door, or did the lady?"

-"The Lady or The Tiger?" (Excerpt)