Since Mary went to Salem to be part of the proceedings (the witch trials), she has become less meek in her attitude toward Elizabeth and John Proctor. She seems strange to them and they are curious about her strangeness. She claims that she is ill, she cries, she presents Elizabeth with a doll (poppet) that she made during the proceedings, she claims that she had never realized until the court proceedings that Goody Osborne sent her spirit out to try to kill her (Mary), when John tells her to go to bed she stamps her foot and says she's 18 and should not be ordered to go to bed for the night, and she tells Elizabeth that her name was mentioned in court that day, but she (Mary) stood up for Elizabeth. The proceedings have given her a measure of fame and importance which has made her bolder, but the proceedings have also scared her which has made her feel ill and uncertain.
The significance of Rev. Hale questioning John Proctor is to serve as foreshadowing. John will be brought to trial, accused of witchery. Also, it is significant that the only commandment that John forgets is "Thou shalt not commit adultery," which is probably the only one John has really broken.