Dr. Patrick does not want to fight, and tells Lizzie to shut her eyes so they can restart their interaction. He asks her on a stroll to see the birds, and tells her that he waited for her the previous night to run away together, but she never appeared. They look in the birdcage and find it empty. Suddenly, Lizzie asks Dr. Patrick if he would help someone die. "You're a precious and unique person, Lizzie, and you shouldn't think things like that," Dr. Patrick replies.
This activates something in Lizzie, and she begins to talk about how her own life is more precious than Mrs. Borden's. She then asks the doctor, "if a dreadful accident occurred...and two people were dying...but you could only save one...Which would you save?" She then asks what Patrick would do if he met a bad person from history, like Attila the Hun. When he insists that he is a doctor, not an assassin, Lizzie suggests that he puts poison out for the slugs in his garden, which is no different. After suggesting that Dr. Patrick would kill if he was sent to war, Lizzie says, "My life is precious!!" and he urges that Mrs. Borden's life is also precious.
Lizzie gets angry at Dr. Patrick and calls him a coward, as Mrs. Borden sits in the parlor with a needle for sewing. Patrick leaves, and Lizzie goes to talk to Mrs. Borden, telling her that Mr. Borden chopped her birds' heads off with an axe. "It's always me who puts the slug poison out because they eat all the flowers and you don't like that, do you? They're bad things, they must die. You see, not all life is precious, is it?" Lizzie says, which makes Mrs. Borden uneasy. She tries to go upstairs when there is a knock at the door.
Lizzie goes to get the door and finds a note from Mr. Borden, which she gives to her stepmother. Mrs. Borden wants to read it upstairs and Lizzie gives her some laundry to bring up to her room for her. She holds Mrs. Borden's arm and asks her what she sees in the reflection of her eyes. "When a person dies, retained on her eye is the image of the last thing she saw. Isn't that interesting?" Lizzie says.
When Mrs. Borden goes upstairs, Lizzie picks up a hand hatchet and follows her up the stairs, saying that, if she were to kill somebody, she would come up behind them. They disappear up the stairs. Afterward, Bridget enters with a pail for washing the windows. Lizzie comes back down the stairs calmly, with the clothes and the hatchet. When she puts the pile down, Bridget picks it up and sees the hatchet. "I have it all figured out, but you have to help me," Lizzie tells the maid, before revealing that she believes her father will leave her the farm now that Mrs. Borden is gone.
Bridget becomes frightened as she realizes what has happened, but Lizzie insists, "Someone broke in and they killed her." Bridget thinks that everyone will realize what happened, but Lizzie implores the maid to help her. "Deny me, and they will kill me," she says, grabbing Bridget's arm. She instructs Bridget to continue washing the windows and leave them open, while she goes into town. Then, she says, Bridget must go next door to have coffee with Lucy until Mr. Borden gets home and finds Mrs. Borden.
Suddenly, Mr. Borden enters unexpectedly. He asks where Mrs. Borden went, and Bridget tries to cover for Lizzie, as Lizzie tells him that Mrs. Borden went out. Lizzie tells Bridget that she ought to go check out a sale downtown, or else go and lie down. Reluctantly, Bridget goes upstairs to lie down.
Left alone with Mr. Borden, Lizzie notes that he is wearing a gold ring that she gave him. "I forgive you, Papa, I forgive you for killing my birds," she says, before undoing his shoes. "I would not want you to find out anything that would make you hate me," Lizzie says. As Mr. Borden takes a nap in his chair, Lizzie raises her hatchet, and there is a blackout just before she brings it down. We hear children singing the song about Lizzie Borden, and the song gets louder and louder and more distorted.
When the lights come back up, the Actress is standing holding the hatchet over the couch, with no one beneath her. Lizzie is at the foot of the stairs and takes the hatchet from her, as Emma calls from upstairs for them to quiet down. Emma comes down the stairs, as Lizzie hides the hatchet behind her back. Emma confronts Lizzie about the fact that she is being visited by the Actress, and people in town are talking. Suddenly, Emma exclaims that she forbids the Actress from visiting.
Lizzie tells Emma she ought to leave if she does not approve of Lizzie's lifestyle, and reveals the hatchet in her hand. "Did you never stop and think that if I did, then you were guilty too?" Lizzie says, implying that she did kill their parents. She elaborates: "It was you who brought me up, like a mother to me. Almost like a mother. Did you ever stop and think that I was like a puppet, your puppet."
Emma asks, "Do you want to drive me mad?" and Lizzie replies, "Oh yes." The Actress takes the hatchet from Lizzie and tells Lizzie that she killed her parents. Lizzie replies, "I didn't. You did." The Actress looks at the hatchet and then the audience.
So much of Lizzie's torment stems from her low self-esteem. When she is talking to Dr. Patrick, she asks him if he thinks that some people are better off dead, clearly referring to her own sense that life might be better if she were not around. When he tells her that she is a "precious and unique person," she is surprised and delighted to hear it. In her slightly crazed state, the affirmation has a strange and haunting effect on her, as she realizes that she deserves to have a good life. No sooner has she realized this, however, than she begins to orchestrate her revenge, suggesting that Mrs. Borden's life is nowhere near as precious.
Part of Lizzie's confusion and crazed state has to do with a certain moral question she has about the nature of life and death. She asks Dr. Patrick if he has a rubric for whose life he would prioritize if he had to choose between the life of a young person and that of an old person, then suggests that Dr. Patrick kills slugs in his garden, even though he says he is not an "assassin." She then suggests that if he went to war, he would have to kill people. In this moment, Lizzie questions everything she has been led to believe about life and death, about who deserves to live and who deserves to die, about the difference between state-sanctioned violence versus criminalized violence.
In this final section of the play, Lizzie proves to be the murderer she is rumored to be. Pollock stages her desperation and altered state as she prepares to murder Mrs. Borden, determined to get her stepmother out of the way so that she can inherit the family farm for herself. She loses her grasp on the sanctity of human life and instead becomes convinced that she can decide who lives or dies. She also imagines that she will only have to kill her stepmother in order to regain power in her family; if she can convince her father that she is not the murderer, he will have no choice but to leave her the farm in his will.
After a rather straightforward reenactment of the events that transpired surrounding Lizzie's parents' murders, the play is transported back into the present, with the Actress no longer representing Lizzie, but herself. She stands above the couch raising a hatchet as if in the middle of the murder, and the real Lizzie takes the hatchet away from her. They are once again in the present moment, where the controversial aspect of Lizzie's life is not the murder of her parents, but her sapphic association with The Actress. Lizzie's sister, Emma, confronts her about her involvement with the Actress, forbidding the Actress from coming to the house. While the problem is very different from Lizzie's problem with her parents, it mirrors that conflict structurally. Just as she felt hemmed in and undervalued by her parents, Lizzie feels held back by her sister, Emma, and even flirts with the idea of murdering her.
Pollock uses theatricality to stage Lizzie's mental instability. Lizzie's impulse to have her lover, the Actress, act out her horrific deed, is a way of obfuscating the responsibility of the deed, putting it on another person. Part of what allows Lizzie to remain remorseless about her act is her sense that she is not solely responsible for the murder of her parents. This is revealed when she suggests to Emma that Emma is partially responsible for the murders, since she raised Lizzie. Then, in the final moment of the play, the Actress tells Lizzie that she killed her parents and Lizzie tells her that it was actually she, the Actress, who did it. By having the Actress "play" Lizzie in the reenactment, Pollock shows the way that Lizzie sees her personal history as fragmented, and does not take responsibility for the murderous act.