(RUTH hesitates, then exits. MAMA stands, at last alone in the living room, her plant on the table before her as the lights start to come down. She looks around at all the walls and ceilings and suddenly, despite herself, while the children call below, a great heaving thing rises in her and she puts her fist to her mouth to stifle it, takes a final desperate look, pulls her coat about her, pats her hat and goes out. The lights dim down. The door opens and she comes back in, grabs her plant, and goes out for the last time). In at least 2 paragraphs, explain to me what Mama is feeling at this point in time. Why is it significant. What change, or moment, in Mama's life does this signify?