A SHOCKING DISCOVERY

A hazmat call at a dialysis center leads to a shocking discovery.

Boden clashes with Paramedic Chief Robinson.

Carver notices a concerning change in Gibson’s behavior.

Air Date: Wednesday, March 27 (9-10 p.m. ET) on NBC.

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CHICAGO FIRE -- "All the Dark" Episode 12008 -- Pictured: (l-r) Joe Minoso as Joe Cruz, Christian Stolte as Randy "Mouch" McHolland, David Eigenberg as Christopher Herrmann -- (Photo by: Adrian S Burrows Sr/NBC)