"Because you are doing it!" Maybe she's just lost her mind. He's frustrated, no, angry about the situation. But he usually keeps a better handle on his temper than this. Other than when he's talking to his mother, of course, but she's not here. It's just this strange, paranoid woman who keeps broadcasting her thoughts into his brain and accusing him of doing it to her.

He continues to edge toward the door. "And why do you keep lying about it?" He needs to get control of himself. He's not thinking clearly. That probably makes it worse, whatever she's doing to him.

Maybe that's why she accused him of being a rapist earlier. So he'd be more vulnerable to her attack.