It's Teresa, let in by Virginia, who tells her in hushed tones how she should tell her sister Catherine that she's lonely, and that's why she should move to her house (rather than explaining any of the problems Virginia and Tommy have been talking about.)
Teresa says that the young couple should leave while she breaks the news, otherwise Catherine will start a big fight.
Virginia says okay, and Tommy comes from the next room to join in on the plan.
The camera zooms out as Teresa moves from the vestibule into the living/dining area, and Catherine comes in from the kitchen to greet her sister.
As they greet each other, it's clear that the two sisters are very different—while Teresa is stoic and warm, Catherine in mouthy and full of complaints about all the aches and pains of old age.
When Teresa says she's just gotten a letter from her newly-married son on his honeymoon, Catherine talks about all the people she knows who have died lately. Tommy and Virginia watch on in the background, looking dismayed and glum.
"You always have such cheerful news," Teresa says, joking, and then rushes the kids out of the apartment so she can get down to business. They say goodbye and leave.
Catherine sets in about what a bad mother Virginia is, the way she treats "my son's baby."
Teresa points out that it's Virginia's baby too. When Catherine argues, her sister says, look, it's not your baby, but her sister isn't listening, launching into the milk-spill incident from the beginning of the movie.
She calls her daughter-in-law a witch, saying she gave her the evil eye.
Teresa waves her off, saying that she wants Catherine to come live with her, that Tommy and Virginia had come over and talked about how things were no good, how they were fighting all the time. (Remember how Tommy and Virginia had tried to control the narrative? Teresa does it her own way.)
Teresa says they're a young couple and they need their alone time. Catherine feels betrayed, yelling how she's "an old garbage bag put in the street," but Teresa says she'll be happier living with her.
Going to the window, Catherine talks about how hard it is to be old and unwanted. Teresa says the two are close, and that she wants to live with her. Catherine says she's afraid of being a little old lady, merely "waiting for the cough." (That's death, folks.) She's fifty-six years old, still vital, still of use, but she's out of a job now, and threatens that this will all happen to Teresa soon enough, when Marty gets married.
Teresa shakes her head, but watches as Catherine resigns herself to her fate. "I'm going to put my things in a bag, and I'm going to come to you tomorrow."
The camera zooms out to the two sisters, sitting quietly.