Nina, encouraged by therapy’s next step, ascends to the attic with Andrew to prove her fears were imaginary. The room is inexplicably dark despite a full moon. When Andrew pulls the cord, blinding bulbs flare, the door slams, and Nina finds herself in the same setup she remembers: cot, bucket, and a mini fridge with three waters.

From behind the door, Andrew instructs Nina on the rigged lighting: a boarded window and ultra-bright bulbs make her choose between agony and pitch blackness. He moralizes that “light is a privilege,” mocks her prior hospitalization, and reminds her the police already blamed her. Nina realizes the dungeon was always real and that he is repeating the abuse under the guise of “discipline.”

Left alone overnight, Nina rations the three water bottles and unscrews one bulb to lessen the glare. She spends the day trapped, dehydrating and worrying about Cecelia, determined not to lose her daughter again. This time she is certain the ordeal is not a delusion.

That night, Andrew returns and offers to let her out only under conditions: she must tell no one or risk being labeled delusional and losing Cecelia, and any future punishment will occur in this room. He belittles Nina’s past, boasts he is always watching, and demands compliance. Dehydrated and powerless, Nina is forced to listen as he presses for her submission.