[s3e19] I Am The Apocalypse -

(Yaya DaCosta): An ER nurse with a past connection to Severide.

Hospital administrator Sharon Goodwin (S. Epatha Merkerson) places the facility under immediate quarantine, trapping members of 51 inside with a potential biohazard and an active electrical fire in the ceiling. [S3E19] I Am The Apocalypse

Severide survives his surgeries but is shaken by the near-death experience. (Yaya DaCosta): An ER nurse with a past

(Oliver Platt): Chief of Psychiatry, whose first meeting with Chief Boden is a fan-favorite moment. [S3E19] I Am The Apocalypse