The conversation provides an opportunity for the girls to express their fear about what has been started by their escapades in the forest. They are worried about the punishment that they will have to endure at the hands of the community.
Especially from Betty, who is terrified at what is being said, particularly by Mary Warren who understands the seriousness of an accusation of witchcraft.
"What'll we do? The village is out! I just come from the farm; the whole country's talkin' witchcraft! They'll be callin us witches. Abby!" Miller (ActI)
"Witchery's a hangin error, a hangin like they done in Boston two year ago!" Miller (Act I)
Betty screams for her mother, Abigail becomes violent with Betty, she slaps her hard across the face, screaming at her to shut up, to never speak of what they did in the forest again.
The conversation also shows the reader that Abigail is the leader of the group. She is in command of the girls behavior from this point on in the play, they will follow her lead, mimicking her as she pretends to see spirits.