What does the nurse do or say in end of act III for Juliet to call her a most wicked fiend romeo and Juliet?

In Act 3, Scene 5, of Romeo and Juliet, the Nurse does not say anything or do any action that would cause Juliet to call her "a most wicked fiend." Rather, it is Juliet herself who accuses Romeo of being a "fiend" in Act 3, Scene 3, when she discovers that Romeo has been exiled for killing Tybalt.