Answer: because struck off entails energy and determination
Explanation: In "The Most Dangerous Game" by Richard Cornell, the author writes struck off instead of walked off because struck off entails energy and determination, is just not only to go away by walking off. Rainsford is being chased by Zaroff. He thinks that running straight is not a good way of escaping from Zaroff. He strikes off to leave no traces in the wilderness and does this recalling dodges of the fox when hunting.