John Proctor has forbidden Mary to go to the court in Salem, where witch trials are taking place, but she goes anyway. John is angry when she returns and threatens to whip her if she does this again. Mary says,
I am sick, I am sick, Mr. Proctor. Pray, pray hurt me not. My insides are all shuddery; I am in the proceedings all day, sir.
When John asks her more questions, it comes out that what is going on in Salem is worse than he had thought. Thirty-nine people are accused of witchcraft, not fourteen; at least one has been sentenced to hang; and Mary, easily impressionable, is sure that an old, poor widow, Sarah Good, who is accused of witchcraft, used a spell to try to choke her in court.
Mary also brings out a rag doll she said she made for Elizabeth in court and mentions that she protected her mistress from a witchcraft allegation.
Mary's declaration about being "sick" works on a several levels. Most obviously, she is using feeling sick to keep John from hurting her. But on a deeper level, the sense of sickness and shuddering inside she feels is a physical manifestation of the psychological unease she is experiencing at what she is participating in. Mary is a weak character who, on one hand, knows what is going on is a lie but lacks the strength of character not to be swept up in the hysteria. She is torn between loyalty to the Proctors and not wanting to go against Abigail. Her sense of sickness foreshadows her role in the sick proceedings that will destroy lives.