Why does Jim grab the light cord at the last minute

Once again, a breeze comes up and puts the rope in a perfect position and Jim cuts through the rest of the rope. Upon this action, the Hispaniola begins to slowly spin and sway with the current. As he is shoving away from the bigger boat in the smaller oracle, Jim catches a rope and hoists himself into a position where he observes the two sailors in a physical struggle, a struggle that to Jim appears deadly.