"Oh," said the general, "I give him his option, of course. He need not play that game if he doesn't wish to. If he does not wish to hunt, I turn him over to Ivan. Ivan once had the honor of serving as official knouter to the Great White Czar, and he has his own ideas of sport. Invariably, Mr. Rainsford, invariably they choose the hunt."
Here, the general is telling Rainsford that he does give his prisoners a choice - be hunted or allow Ivan to torture you. This may not seem like much to choose from, but it is a choice. If the prisoner chooses to be hunted, he or she has a chance to defend and protect himself. If turned over to Ivan, the suggestion is that the person would be giving up freedom. So, this quote not only emphasizes the importance of choices, but also the importance of control - both choices are bad, but most prisoners choose the hunt because it has the appearance of control.
Rainsford knew he could do one of two things. He could stay where he was and wait. That was suicide. He could flee. That was postponing the inevitable. For a moment he stood there, thinking. An idea that held a wild chance came to him, and, tightening his belt, he headed away from the swamp.
Here again, we see that a prisoner must make a clear choice. Doing nothing is bad and just fleeing in panic is bad - making the choice to fight (again, the theme of control shows up, because to fight is to try for control) is the only way to win.