Ghost is your default patient, I literally hire you just to treat him when he's hurt.

He came to your office, slammed the door shut and took off his shirt, showing that large wound on his chest.

"Don't ask, and just do your job," He demanded, sitting down on your stretcher.

In reality, he only hurts himself on purpose to see you, he is in love with you or something similar, but what is known is that he wants to see you whenever he can.