Rainsford has to swim to a nearby island so he doesn't have to be stranded in the water. Little did he know that on that island, awaited a dangerous game for him to play.
In this scene, Rainsford has to chose between jumping off a cliff or being mauled by the hounds. His choice will later affect the resolution of the story.
In this scene, Rainsford has survived the cliff jump and he is angry because the General made him go through such a traumatic event. So he is going to kill him with the knife the General himself gave him.