In the beginning, Mary agrees to go with John Proctor and testify against Abigail in court, but then when actually in court, she flakes under pressure and accuses Proctor of witchcraft and joins...
John Proctor is angry at Mary Warren for going to court because he forbid her not to. He believed that the trials were wrong and since she was his servant, he didn't want her to be a part of it.Later...