Upton is torn between helping track down the perp and providing emotional support to the scared young girl that needs her on Chicago PD. "Infection Part 3" is the fourth episode of the show's seventh season.
Ruzek: You and your ex-husband built a panic room. Some of this must make sense. Seldon's wife: For when an outbreak happened, not for when he caused one. My ex-husband is not crazy, he's not a monster, he dedicated his whole life to infectious disease, and it's not paranoia. It's fear, it's educated and grounded fear. And look, all you have to do is turn on the news to see that there are a thousand ways the world could end. I mean, there's climate change, and there's famine, and there's the war, and then there's lack of water, and there's disease. And the right outbreak at the right time with the right factors, it could end this race within months and that's not paranoia. That is a truth that people can't handle looking at. And he had to look at it every single day.