Karyn was the one that blasted Zoe with the Mental Gun.
Zoe looked down at herself. "Oh god," she said. "This is so freakin' weird."
"Zoe?" Jon asked.
His sister looked up at him and shook her head.
"She thinks she's me, Jon," Karyn said. "Remember?"
"Oh, yeah."
Jon walked over to his sister. "Are you okay?"
"I'm stuck in your sister's body. How okay do you think I am?"
"Well, you're not really Karyn. This gun just makes you think you're her."
"What's the difference?" Zoe walked past him and walked upstairs.
"Where are you going?" Jon called after her.
"To get the stone, of course. I have to get my body back."
Jon and Karyn looked at each other, then ran after her. "Wait, Zoe!"
Jon cursed himself. He should have just blasted her again with the gun (thus reversing the effect) and been done with it. But now she was going to use the stone? Who knew what she'd do to herself?