Faults:-
1.They can built there house in a noise area like waterfall.
2.At starting there was no pin in the stairs later on it shows up all of a sudden, the lady didn't saw where the sack was stucked.
3.She could give birth to her child near the waterfall.
4.The house's every door was open. Why there was no safety.
5.sacrifice part:- I think he forgot that he if he dies her family will die since there will be no one to feed his family since till now only he visited the hunting areas.
I believe that he must be carried something which will make some noise when someone though them(ex:- bells, crackers). By using this trick he could through the crackers to distract them.