In chapter 7 of Freak the Mighty, Max, with Kevin riding high on his shoulders, runs into the nasty mill pond to escape from Tony D., also known as Blade. This works, but Blade and his gang stand at the shore and throw rocks at Kevin and Max. With his legs stuck in the deep mud, Max can't get out of the way of the rocks. Max is pretty sure that there is no possibility of escape, but Freak comes to the rescue.
To get the attention of the police, whom Kevin refers to as the "calvary," Kevin starts whistling very loudly. In fact, he whistles so loudly that it hurts Max's ears. This attracts the attention of the police, who are patrolling the area around the pond. From their car, the police shine a bright light on the boys out in the lake. Kevin wildly waves his arms, and the police tell them over a megaphone to stay right where they are. The attention of the police is enough to force Blade and his gang to run away. Kevin shouts to the police that they need their help. The cops come out with a boat and ropes to pull the boys from the pond.