They ran out of money when..,
It seemed like they ran out of story writing funds when it came to summoning the spirit of Moira and making her go away. I mean ZERO imagination in "I wish they were all dead" and "I don't need you anymore".
It would have been better off to eliminate the whole Moira spirit ghost storyline and this just to have been about the "school" or whatever it was in the dessert being run by messed up people who were in it for the money and abused the kids for their own amusement with no super natural stuff.