Buddy's human was injured in some sort of explosion in his garage. The man was able to get the door opened to let the dog out, and somehow the dog sensed that he needed help. The policeman was not sure where he was going until he saw the dog. If you look carefully, you will see the dog turn around to make sure the car was still following.
Dogs are amazing. As I have talked about previously I have problems with depression and my dog Tasha would come and put her paws on my shoulders when I was going through some difficult times.