[Hester] dragged a metal lever out of the winch and swung it at Wreyland. [...] Hester lurched forward and raised the bar again, but before she could bring it down on the old man's skull Tom grabbed her arm. "Stop! You'll kill him!" "So?" She swung toward him, snaggleteeth bared, looking like a demented monkey. (9.22)
This is a strong image, one that again equates violence with primal, animalistic behavior. Hester doesn't have a problem with violence, because her parents were killed right in front of her. To her, it seems to be the only way to solve a problem.