Karyn ran after him as fast as she could. She wanted to be within the "safety radius" when he used the device. She didn't want to forget this reality.
As she ran, she noticed the front door of the McMillan house opening.
"Jon, wait!" Karyn yelled. "Wait for me!"
But Jon didn't stop. He kept running until he was standing on the McMillan's front lawn. As he stood there, he watched as someone emerged from the house. Assuming that it was Sarah, he fired off the device.
Unfortunately, Karyn wasn't within five feet of the device, so her memories changed to fit the new reality, whatever it was.
