Abandoned

Shannon & Jack

Shannon's father Adam was in a car crash with Jack's future wife Sarah. When Shannon and her step-mom go to the hospital we see Jack go by her in the hallway.  In Man of Science, Man of Faith, Jack made a decision to keep working on saving Sarah's life instead of helping trying to save the man she collided with whose last name was Rutherford.  In Abandoned we learn this man was Shannon Rutherford's father.