“One cannot commit evil in evil” 

In a place where everything is evil—the Judge cites a prison as an example—evil is no longer remarkable. In some ways, it ceases to exist, because it is what passes for normalcy. The fantasies acted out in the brothel are relatively innocent in this way, because the brothel itself is a place of questionable morality.  

“You have no idea of how we really feel. You observe it all from a distance” 

Carmen tells Irma that even though she is in charge of the brothel, she does not understand the girls who work for her, because she operates at a remove. It is a common condition of power relationships that the more powerful party lacks the ability to empathize with the less powerful. 

“One can hear all that’s going on in the street. Which means that from the street one can hear what’s going on in this house” 

There is a strange disconnect in this statement. It is impossible to hear everything that is going on in the street, because Irma has soundproofed the rooms. And it is impossible for those outside to hear everything in the brothel, because providing discretion is one of the brothel’s purposes. The quote is an unconscious reminder for all of the characters that they are vulnerable.