Will's change of expression is subtle, just a little more interest. He's taking note of similarities he feels about Julien and about his own roommate. Someone used to a far different set of cultural identifiers, abstracting his world to explain it. It is a theory in process, one of the many newly opened files in his mind where he stores information. The initial thought of where Julien might fit amongst them is noted.

"Sometimes I do the same thing." It's a bitter observation, though Will's tone is easy enough that without context, it does not strike as such. "Currently, I teach criminal theory to officers."