Hazel and Peter appear in the Mannon sitting room. Orin is heard in the hall calling his mother. A number of ancestral portraits bedeck the walls, including one of a minister of the witch-burning era and one of Abe Mannon. Orin and Christine enter, the former questioning his mother suspiciously. A lie about a fainting spell immediately mollifies him.
Orin boyishly revels in being coddled by Hazel and Christine. He then jealously recalls how Lavinia is always coddling Father, causing his mother shudder in horror. He is speaking as if Ezra is still alive. Orin remarks strangely that Ezra remains: "He's the same and always will be—here—the same!" Orin somewhat bitterly notes that Christine has changed a great deal; she is more beautiful than ever and younger somehow. Lavinia silently appears in the doorway.
Recalling how long ago Hazel saw him off to the war, Orin harshly declares that they ought to send the women out to the battlefield so they would stop gabbing about their heroes. He apologizes and recalls how the memory of her singing, dreams of Mother, and memory of Lavinia's bossing him around reminded him of life while he was in battle.
Lavinia orders Orin to come see Ezra in their father's brusque, commanding tone. Orin mechanically stands and salutes, and then shamefacedly starts in confusion. Christine protests and implores Orin to stay. He immediately relents, and Lavinia stalks off. An uncomfortable Hazel and Peter excuse themselves. Christine urges Hazel to come back soon.
Suspiciously Orin asks why Christine has suddenly taken to Hazel. He only made a show of liking her long ago to make her jealous, but now Christine is a widow. He wonders why she is trying to rid herself of him and why she has only written him twice in six months.
Orin asks Christine about Captain Brant. Prepared, Christine explains that Lavinia has gone mad and begun to accuse her of the impossible. Only Orin is her "flesh and blood," while Lavinia is Father's. Christine recalls the secret world she shared with Orin in his childhood with their unforgivable password, "No Mannons allowed," and reveals that Ezra always hated Orin jealously.
In Mourning Becomes Electra you write: "Oedipus was the Theban king who unwittingly killed his father and MURDERED his mother." [Emphasis mine].
It should read: "Oedipus...MARRIED his mother!"
(Oedipus' mother Jocasta did commit suicide after learning her lover was her son. Oedipus however did NOT "murder" her.)