There was a pause, so long that she thought it might be safe to pick up her knife and fork again, but as she stirred her mother said, “I want you to tell me what you are sulking about, Isobel.”
She was really frightened now, wondering how long she would hold out, foreseeing the moment when she would begin to scream and scream. She wasn't going to, not ever. She would think of grace and be still.
“Tell me.” Her mother's voice, which had been rising to a scream, turned calm and gracious again. Like somebody getting dressed. Isobel looked up and saw that her eyes were frantic bright. She doesn't want me to tell her, she wants me to scream. I do something for her when I scream.
Then she saw that her mother's anger was a live animal tormenting her, that she Isobel was an outlet that gave some relief and she was torturing her by withholding it.