Mary took off the guard and the rock still

Mary took off the guard and the rock still flew out. Rock hit a dog. The dog was so frightened that it ran out in front of a car. The driver of the car slammed on the brakes so hard that his passenger (who was not wearing a seat belt) flew through the windshield and suffered very serious injuries. Now, the passenger is suing the driver and also, Mary. The passenger alleges that Mary's actions are the root cause of all the damages. What do you think?