"Doctor...Doctor...Doctor...Doctor...Doctor. How many doctors are there on this planet?"
prot asks Powell's wife about a picture of a young man in their home.
Rachel: That's Michael. Mark's son from his first marriage. prot: How many marriages has he had? Rachel: Just the two. So far. prot:so far?
During prot's going-away party, Howie is collecting essays from the patients telling prot why they feel they should be the one he takes back to K-PAX. Then one of the hospital staff hands one in and backs away with a shrug.
Later, the same staff member is guarding prot's door overnight, and when another staff member passes by they make an on-the-spot bet on if prot is actually going to leave or not.
After prot returns from his trip "up north", Powell is angry with him maintaining he really did leave, leading to this exchange.
Dr. Powell "What would you say if I were to tell you that I don't think you took any trip at all, to Greenland or Iceland or anywhere? That I don't believe you're from K-PAX? I believe you're as human as I am?" prot: "I would say you're in need of a thorazine drip, doctor."