Rainsford is an honorable man who has only been sucked into Zaroff's game through the fateful events that surrounded his arrival on the island. Though Zaroff's game is one that involves murder, he, too, is a man of his word, and he plays the game according to the rules he has established. Rainsford's desire for revenge also seems to have overwhelmed the sense of fair play and humanity which he displayed earlier when he called Zaroff's human hunt an act of murder. Rainsford is not a murderer, and bushwacking Zaroff would be just that. Rainsford decides to allow Zaroff to play the game in order to give the Russian a taste of his own medicine because it is the only fair way for him to settle the score. And Rainsford may have actually taken to Zaroff's new game a little, and by playing it one more time, he will be able to find out for himself who the better man is.
"The Most Dangerous Game" is quite a long story for its genre. This is because so much space had to be used in the initial exposition. The author had to explain how Rainsford got to the island in the first place. Then he had to explain Zaroff's background, philosophy, and his hobby of killing humans for sport. Then there was the long chase, which is the main part of the story. The author may have felt that a description of some sort of fight between the two men would take up too much additional space. Their final battle is not described, but it is obvious that Rainsford won. It would seem that they had a duel with swords because Zaroff says, "On guard, Rainsford." Whatever weapons they used, Rainsford slept in Zaroff's bed that night.
In the film version of the story made in 1932, and available on DVD, the two men have a violent battle in which the General tries to kill Rainsford with a powerful hunting bow but ends up mortally wounded and falling to be devoured by his voracious hunting dogs. This is the sort of battle Connell might have described in his story if he hadn't been concerned about length. Also, he might have figured that the more important contest was the one that took place outdoors when Zaroff was tracking Rainsford all over the island. Rainsford had already won their deadly game.
Please refer to the third link below for questions and answers regarding "Ending."
One gets the impression that this long short story might have originally been started by the author with the intention of turning it into a novel. There are many parts that could have easily been made into full chapters. The opening scene could make a chapter with the introduction of Whitney and Rainsford, their discussion of hunting, their discussion of Ship-Trap Island, and other exposition via dialogue. The chapter would end neatly with the following dialogue:
"I'm not sleepy," said Rainsford. "I'm going to smoke another pipe up on the afterdeck."
"Good night, then, Rainsford. See you at breakfast."
"Right. Good night, Whitney."
In the second chapter Rainsford would fall into the shark-infested Caribbean and swim to the island. In the third chapter he would find his way to the "palatial chateau" with great difficulty and knock at the door. That chapter would end with the bearded giant opening the door and pointing a long-barreled revolver at Rainsford's heart. A good ending for that chapter would be:
"Don't be alarmed," said Rainsford, with a smile which he which he hoped was disarming. "I'm no robber. I fell off a yacht, My name is Sanger Rainsford of New York City."
There is plenty of material for a short novel. It would take about five chapters of exposition and dialogue before the big chase had even begun. If Connell had written the story as a novel he would have given many thousands of words to the finale and described the deadly fight between Rainsford and Zaroff. He might have also devoted at least one full chapter to telling how Rainsford made it from one side of the cove to the chateau and into Zaroff's bedroom. But there is a big gap after this cliffhanger:
Rainsford hesitated. He heard the hounds. Then he leaped far out into the sea. . . .
It seems probable that Connell got tired of his plot and decided to end it quickly and submit it as a short story. When the motion picture adaptation was made in 1932, the big fight between Zaroff and Rainsford which seems to be conspicuous by its absence in the original story was written in by the screen writers and provides a more satisfactory ending that the cryptic line which ends Connell's tale:
He had never slept in a better bed, Rainsford decided.