Chicago Fire "Viral" episode 16 airs Wednesday, Feb 20 2013 on NBC (10-11 p.m. ET).
Episode Synopsis: The anguish that haunts Cruz (Joe Minoso) over his previous actions boils over, as he puts himself and his fellow firefighters in jeopardy. Casey (Jesse Spencer) and his sister Christie (guest star Nicole Forester) try to solve their issues with their mother (guest star Kathleen Quinlan) and each other. Meanwhile, Severide (Taylor Kinney) reaches out again to an important person from his past as a favor to Lieutenant Whaley (guest star Shane McRae) and the squad gains new perspective after assisting the bomb squad on an extremely dangerous call. Charlie Barnett, Monica Raymund, Lauren German, David Eigenberg and Eamonn Walker also star. Shiri Appleby also guest stars.