One of Chicago P.D.'s beloved characters faced being infected with the dangerous bacteria killing people during the crossover event, and fans were not O.K. The three-hour crossover event brought Chicago Fire, Chicago Med and Chicago P.D. characters together to fight the mysterious disease. While the episode had tensions high throughout the event, when one of the member of the Intelligence Unit found themselves in quarantine, things took a dramatic turn.
Spoilers ahead for Chicago Fire, Chicago P.D., Chicago Med crossover event, "Infection":
After firehouse 51 responded to a fire at the science building of the local university and discovered a connection between the incident and the infection, Upton (Tracy Spiridakos) took on the task of interviewing employees who had a connection to the first victim of the disease.
Jay (Jesse Lee Soffer) calls her and points her to one lab assistant who was supposed to be in the building when the fire started, but who conveniently skipped work the day.
When she arrives at the woman's home she knocks, after a few attempts, the woman opens the door and is visibly sick. Upton still goes into her home and attempts to ask her abut the case, but the woman collapses after she tries to talk.
The scene takes a grim turn after Upton holds on to the woman and realizes her blood is all over her. She then uncovers part of her body and sees the blood is coming from an open wound given by the dangerous infection.
Fans were shocked at the big twist, and hoped Upton would be spared from the lethal disease.
SOMETHING IS NOT RIGHT ! #CHICAGOMED— KHAMyAH . ❤️ (@trEATME_GOOD_) October 17, 2019
Later, Upton arrives at the hospital and tells Will (Nick Gehlfuss) the woman collapsed on her and that's she's covered in her blood. Will tells her not to move while he gets help for his friend.
Natalie (Torrey DeVitto) later checks Haley's body closely. She asks about the victim who come in with her, as the episode shows Dr. Marcel (Dominic Rains) struggling to salvage her damaged skin tissue in surgery. Natalie then finds one tiny cut in Upton's finger, meaning she could have contracted the infection.
When the woman Upton brought in dies in surgery, the last known connection to the bacteria dies with her and Sharon (S. Epatha Merkerson), alog with the CDC, order a quarantine.
Upton gets caught in quarantine with the residents of an apartment building where the person responsible killed the most people with the disease. Haley helps a teenage named Amanda to stay calm during the frightening situation. They also go through the other quarantine people's strange mutiny, which ends with them rushing out of the hospital, only to be quickly captured by the police.
The quarantine scene also offers a look into Upton's past, and she admits Trudy Platt (Amy Morton) inspired her to become a police officer. She recalls how she was the victim of a crime in the past and a young Trudy was the officer leading the investigation on her case. Seeing her command a room and be a leader made her dream to be like her one day.
Natalie later visits quarantine and reveals Upton's samples came back clear so she is safe to leave and continue to help with the investigation. She stays close by to support Amanda for the rest of the stressful crossover.