The play is, at its core, preposterous. That it works at all is because Mr. Mastrosimone keeps the action moving so fast there's not enough time to consider the absurdity of the material until it's over. Of the four characters, the three women are merely rough sketches of human beings. We know little about them, and we learn nothing about how this traumatic event affects their lives.

Mr. Mastrosimone entertains and embellishes the terrible myths that women invite attack by their sexual mannerisms and mode of dress. Terry, the dim-witted roommate, is given a monologue in which she tells about being raped as a young girl. She was, she remembers, wearing snug- fitting pink tights, part of her Tinkerbell costume for a party. ''It was all my fault,'' she says. Along these same lines Marjorie is accused by her roommates, as well as by the rapist, of being a tease and inviting rape.

Marjorie, as beautifully played by Linda Berns, is a cool sophisticate seething with suppressed rage. She has a mean streak as wide as the rapist's, and her sadistic retribution on him is terrifying.

Terry, the empty-headed roommate who is befuddled by the existence of the loud-mouthed man hanging from chains in her fireplace, is played by Linda Lee Reichel with touching simplicity. This Terry is a spineless woman whose self-image is, at best, that of a dishrag. She is easily convinced by Marjorie to assist in the planned burial, and she is equally quickly manipulated by the rapist into defying Marjorie.

The third roommate, Patricia, expertly played by Jan Anderson, is a caricature of a liberal social worker. She sees the rapist as a misguided man who needs help and encouragement to get over his nasty tendency toward violence. Patricia acts like a cheerleader, exhorting everyone to stick to the facts, and define their terms. Miss Anderson creditably adds depth and sensitivity to the role of Patricia not apparent from the script.