Realizing a conventional interrogation won't break Elliott, Lily adopts a psychological approach, essentially "taking him off the leash" to see where he runs.
In the second episode of A Spy Among Friends , titled the narrative tightens its grip on the psychological fallout of Kim Philby’s defection. If the premiere was about the shock of betrayal, this hour is about the agonizing post-mortem—the "how did we miss this?" that haunts Nicholas Elliott and consumes investigator Lily Thomas. The Three-Way Interrogation
The Ghost of Philby: Friendship, Betrayal, and "The Admiral’s Glass"