When Abigail threatens Judge Danforth, a full sense of Abigail's determination is revealed. Abigail is determined to get her way. She does not relent for anything. Social conventions, ethical notions of the good, and even the law do not stand in the way of what she covets. In threatening Judge Danforth, the reader gains a true sense of that determination, an intrinsic part of her characterization.
Another revelation that is evident when Abigail threatens Judge Danforth is that Abigail is the center of the Salem Witch Trials. She is in control of them. The fact that she feels empowered enough to threaten a sitting judge is a reflection of this. In threatening Judge Danforth, the reader becomes fully aware of how the trials are more about what she wants than anything else. The threat to Judge Danforth and his eventual coddling of her reflect how Abigail is the center of attention. As a result, it becomes clear that Proctor does not stand a chance. She has generated so much inertia for his claims of truth and morality that it is impossible to stop what has been started. This becomes clear when Abigail is able to control even those who sit in judgement of the accused.