how did rainsford get back to the Chateau?

Ransom hears Zaroff and his hounds coming for him. Rainsford has exhausted all his hunting tricks. He decides to jump off a cliff into the ocean, "Twenty feet below him the sea rumbled and hissed. Rainsford hesitated. He heard the hounds. Then he leaped far out into the sea. . . ." Rainsford then swims back to the Chateau undetected by Zaroff.