1. A Test of Character: Rebecca Nurse's sudden appearance serves as a moral challenge and a test of character for John Proctor. Just as Proctor is about to sign a false confession to save his life and protect his family, Rebecca's arrival forces him to confront the conflict between self-preservation and moral integrity.
2. A Moral Compass: Rebecca Nurse represents a moral compass within the play. Her unwavering commitment to truth, justice, and righteousness stands in stark contrast to the moral chaos and hysteria consuming Salem. Her presence reminds John Proctor of the principles he should uphold, even in the face of dire consequences.
3. Symbol of Innocence: Rebecca Nurse is widely respected in the community and is known for her goodness, kindness, and purity. By juxtaposing her arrival with John Proctor's moment of moral struggle, Miller highlights the conflict between the forces of good and evil in the play. Rebecca's presence emphasizes the gravity of the choices John Proctor must make.
4. Dramatic Tension: The sudden appearance of Rebecca Nurse creates dramatic tension and suspense. As the audience becomes aware of her reputation and the danger she faces, they are drawn into the moral dilemma confronting John Proctor. The moment is heightened, raising the stakes and intensifying the audience's involvement in the story.
5. Thematic Contrast: Rebecca Nurse's appearance provides a stark contrast to the deceitful and manipulative actions of other characters in the play. Her presence underscores the themes of truth, honor, and the destructive consequences of lies and hypocrisy.
6. Moment of Choice: Rebecca's arrival forces John Proctor to make an immediate decision between confessing falsely to save himself or standing by his principles, leading to his ultimate act of heroism and redemption.
In conclusion, the appearance of Rebecca Nurse at a critical juncture in John Proctor's decision-making process serves as a powerful structural device that underscores the play's central themes, heightens dramatic tension, and provides a moral counterbalance to the darkness prevailing in the town of Salem.