He got more than just liver IMO. 4 hours is minimum....I just recently read an article by Bill Winke who stated the same thing. A gun shot liver hit deer can be tracked almost immediately but he recommended 2 hours, a broadhead hit liver, 4 hours.

The point of the Recovery thread mentions, if you don't see or hear the animal go down, WAIT the appropriate amount of time. You'll lose more animals than you'll recover by not waiting.