Spoilers for this episode.
Jack is being taken back to CTU after disobeying the order at the mall when Nathanson offers information on the gas. Audrey passes the call to Jack, who escapes Curtis' custody and meets the man privately. Chloe erases Audrey's telephone records to hide their contact, drawing McGill's suspicion. Nathanson is being hunted by the people he worked with, and Jack reaches him as armed men close in on the building.
Nathanson survives long enough to give Jack a computer chip, but dies after being hit by fire from a helicopter. Chloe examines the data with Audrey's help and uncovers a connection between the gas and companies linked to Omicron. Jack recognizes Omicron and asks Chloe to check for Christopher Henderson; she confirms that he is an executive there. At CTU, McGill interprets the staff's secrecy as disloyalty, has Buchanan detained and begins monitoring communications, making it harder to pass the new lead to Jack.
Vladimir Bierko tells Logan that Erwich is dead and demands President Suvarov's motorcade route. If Logan refuses, he threatens further gas attacks against American civilians. Logan allows Novick to hand over the information despite the consequences for the Russian visitors. Martha learns of the bargain and pleads with her husband to stop it. When he will not, she joins the Suvarovs' limousine, forcing her husband to face the danger to her as well.