One aspect of the play that you could think about in response to this question is the use of the mirror in the very final scene, when Gerardo and Paulina enter a concert hall and there is a mirror against the back of the wall that both allow these two principal characters to look at themselves as they hear "Death and the Maiden" play but also force the audience to look at themselves too. The significant way in which Gerardo and Paulina lock eyes on each other for a moment when this music begins combined with the mirror is very important in terms of the way in which the playwright communicates one of the central themes of this play and the whole element of catharsis.
Dorfman once said in an interview that the play is "not a play about somebody else, it's a play about [the audience]." The mirror in the final scene acts as a device therefore that implicates the audience in the moral dilemma that we have seen played out before us. It forces them to consider how they would respond in such a situation and what they do with a culture of torture, fear and terror that lies in a past that refuses to stay still and silent. The mirror indicates to the audience that that conflict is still ongoing, and that it involves them, too.