During the car ride, Ian dropped the idea of having sex with Mina, who was quiet and withdrawn. He knew she was not sick; there were no clots in her brain that would move, nor was there any danger in telling her the past. Her headaches likely came from the stress of trying to remember, and the only things that stopped her from confirming was her trust in him, and the fact that she believed the added stress would be deadly. Jeremy believed that Mina's mind blocked out the old memories the same way a person who went through a traumatizing experience would sometimes blackout. They never found where she was being held, so they could not confirm, but they all agreed that she must have had to do something so terrible to get away that her mind literally cracked, 'forgetting' the bad, so it could focus on only the good.
"You're quiet."
"I'm not trying to be," Mina replied. "I was just thinking about our relationship."
"Do you want to call off the wedding?"