Maybe the queen took Kathryn’s fake memories away. Then Kathryn would have woken up in a car, driving. She would have had no idea what to do and would have crashed the car. She wouldn’t know where she was or where to go back to so maybe she would have just wandered off into the woods. If there are places that are similar in both worlds maybe she will find a place like that. I could just imagine her wandering around with no memories at all. And if it is at least half an hour drive to the border that is a large enough bit of land to get lost in.