Duncan nimbly climbed the reef and stood atop it.
He saw a small stream of water trickling downwards to the reef from the other end and falling off the reef. Duncan cautiously made his way tracing back the stream of water. He didn't want to make camp and then find out later that he had intruded upon some other cannibal's territory.
Duncan wasn't keen on engaging in another fight before he restored his qi. And if there was a cannibal here, then it was probably stronger than other cannibals to occupy such a nice place. So, it was imperative that he figured out if there was any danger here.
Following the stream, Duncan came to a tunnel of sorts that wasn't visible until the moment he came near to it. Duncan saw the stream coming through it. After hesitating a bit, Duncan decided to check it out and stepped into this hidden tunnel, and made his way inside.