If Rainsford wins the hunt what does Zaroff promise him?

The "promise" made by Zaroff is that Rainsford will be allowed to leave the island if he manages to evade Zaroff in the hunt for three days; however, the reader is left to make a judgment call as to whether he is to be trusted or not.  Please do keep in mind that this is the same man who hunts people for fun; in the end, we are left, once again, to make a decision.  What does Rainsford do with Zaroff in the end, once he has him at his mercy in Zaroff's bedroom?  Do you release a master hunter back into the jungle and give him the opportunity to hunt you down again, or do you become a killer yourself and sleep at peace?