Basic medical privacy question in the New York Times Magazine

A very basic medical privacy question is in this week's "The Ethicist" by Randy Cohen in the New York Times Magazine:

The New York Times > Magazine > The Ethicist::

"I am a medical student at a major hospital. A patient who said he was a high-school teacher, depressed and suicidal, turns out to be a convicted felon wanted for parole violations, among other nonviolent crimes. The law dictates that we treat him like other patients, but his rapid recovery was suspicious. He is ''well'' enough to be discharged. Would it be ethical if when he leaves the hospital, the police ''happen'' to be waiting? Anonymous, New York."

For Randy Cohen's sensible answer - which doesn't mention a single privacy law - click here (no subscription required).