Patrick Fitzgerald is the kind of guy people want to listen to. He still holds an outsize reputation among top federal prosecutors in Chicago, having served in the role for a record 11 years and successfully prosecuted two Illinois governors.

So it may be no surprise if a former student decided to sit in on one of the classes co-taught by Fitzgerald and fellow Skadden, Arps, Slate, Meagher & Flom commercial litigation partner Michael Scudder Jr. at The University of Chicago. And that’s exactly what Fitzgerald thought was happening a little over a year ago when a federal law clerk walked into his class with a suit on. But it turned out the former student with a few hours to kill had just walked into the wrong classroom.