So, what was the point of the tribe with the human sacrifices?
The basic Chekhov's gun principle: "One must never place a loaded rifle on the stage if it isn't going to go off. It's wrong to make promises you don't mean to keep."
In this movie, there is a tribe, supposedly from a neighboring island, that goes to the main character's island for their rituals and human sacrifices. However, those natives never discover the main characters. There is no chase, no fight, no being taken prisoners... So what's the point of including them? What role do they play in this story?