Isaac's "things that life is worth living" speech ends with him musing, "Tracy's face".
Series
In "Last Reasoning of Kings", it's a very somber and tired Niels Bohr who tells Charlie,
Niels Bohr: Earlier today I asked you, "is it big enough?" Is it big enough?
Charlie: (mentally calculating) 20 kilotons, burn radius two miles wide. If you spotted a flaw in the math...
Bohr: There was a chemist once in Germany. He made artificial fertilizer. And when the last war came, he thought, "perhaps I could fashion my work into a weapon". Some thought it to be so intolerable, it would discourage any future wars. But his legacy is a fog of chlorine gas that crept over Europe and Africa and Asia. When I asked "is it big enough", I meant is it big enough that no sane person would ever dare to use it?
Charlie: (at a loss, then replies) I don't know.
Bohr: Good men invent bigger and more efficient methods for humankind to exterminate itself, hoping the world will lose its hunger for horror. But our species seems to have an insatiable appetite. (beat) I've lost mine.
In "The Second Coming", Abby's parents tell her that some distant relatives in the Soviet Union have been captured by the Nazis as part of their "ghetto relocation" program. Her parents are clearly unnerved and under no illusions about what that really means. Then later, she gets an intelligence file sneaked over to her by Dunlavey. It has pictures.
In "The Understudy", Liza borrows a Geiger counter to check for radiation in her house. Unfortunately for her, it appears to be registering only background when she tries to show Frank what is happening, and he thinks she's just gone crazy.
In "Tangier", Abby has to give up Elodie if it means helping Charlie get revenge on Lancefield.
In "The Gun Model", Abby finds one of Elodie's playing cards and lashes out at the new arrival at Elodie's old house.
