Explain how the mystery of Eddie Willers' unnamed friend in the cafeteria and the shadowy man Dagny sees outside her office add to the suspense of the novel.

While most people believe that John Galt is only a figment of imagination, these mysterious appearances reinforce the idea that there really is a John Galt. Rand also reinforced that idea in the previous chapter when Dr. Stadler talks about three former students of his at Patrick Henry University but names only two.