Most of the time, if there is an intervening cause between your negligent action and the injury, you will not be held liable, but that isn't always the case. If you create an unsafe condition, and someone else steps in and tries to make it safe, but fails in their attempt, they are not liable, you are still liable. For example, in the case of Pacht v. Morris (107 Ariz. 392, 489 P.2d 29 (1971)), Pacht hit and killed a horse with his car. He drove off leaving the horse in the middle of the road. Another motorist alerted a police officer who stopped his police car near the horse, and shone a spotlight on it. Morris drove up, didn't notice the horse and crashed into it. The Court found that Pacht was liable, despite the fact that he could not have moved the horse himself and that the police car provided a better warning that Pacht could have.