Carol Coulson is Joan Fergusons long suffering neighbour under the regime of her drunken husband. She kills her husband by stabbing him with a kitchen knife. Joan knocks on the door and enters just as she stabs him, she holds Joan and her own daughter Jill hostages until the police can arrest her. Coulson is one of few prisoners who gets to seee the softer side of Ferguson. Joan treats her nicely and actually tries to help her with anything she can.
She is later found hanged in her cell by Joan Ferguson and the governor. Joan takes it on herself to inform Carols daughter Jill of her mothers death.