When Rev Parris leaves, what does Abigail, Mercy, Mary & Betty's discussion reveal and how does it hint at events that will occur later?

The discussion between the girls reveals what has actually occurred in the woods. The girls were dancing around a fire. It also comes out that Abigail drank blood in order to cast a spell to kill Elizabeth Proctor. When Mary Warren pleads with the girls to confess to dancing, Abigail's ruthless nature is revealed. She threatens the girls, telling them she will come in the night and kill them if they tell of what happened. Abigail is clearly in control of the girls, and they fear her vengeance. This discussion leads us to believe that later on the girls will be too afraid of Abigail to change their stories. It also reveals that because of her ruthlessness, Abigail will eventually succeed in her original mission, to kill Elizabeth Proctor. It reveals that Abigail’s manipulation of others and powerful presence will eventually persuade the courts to take her side.