Answer:
The detail from the excerpt that best supports his idea that Rainsford is unchanged and still feels that the hunter is justified in killing the hunted is:
* Rainsford did not smile. "I am still a beast at bay," he said, in a low, hoarse voice. "Get ready, General Zaroff."
Explanation:
The question is not complete since it does not provide the excerpt, here is the excerpt:
Read the excerpt from "The Most Dangerous Game."
A man, who had been hiding in the curtains of the bed, was standing there.
"Rainsford!" screamed the general. "How in God's name did you get here?"
"Swam," said Rainsford. "I found it quicker than walking through the
jungle."
The general sucked in his breath and smiled. "I congratulate you," he said. "You have won the game."
Rainsford did not smile. "I am still a beast at bay," he said, in a low, hoarse voice. "Get ready, General Zaroff."
The general made one of his deepest bows. "I see," he said. "Splendid! One of us is to furnish a repast for the hounds. The other will sleep in this very excellent bed. On guard, Rainsford." . . .
He had never slept in a better bed, Rainsford decided.
The story "The Most Dangerous Game " by Richard Connell tells the story of people trying to survive o a manhunter, here in this excerpt we can see how Rainsford after an extremely hard adventure continues thinking that the hunter has the right when he says "I am still a beast at bay," and "Get ready, General Zaroff.", he is ready to kill and so he does, right before going to bed.