Mercury

Plot hole: Not far into the movie, Starla decides to check out the basement to see what Grant's been up to. As soon as the door is opened she reels from the stench and we discover that it's full of rotting meat and dead animals. In reality, the whole house would have smelt like an abattoir for days before hand and the stench would have permeated out into the neighbourhood. A non-airtight wooden door would not have kept that kind of smell located to the basement only.

Mercury

Plot hole: The police are on the trail of a known psychotic and mass murderer. When they turn up at the house of the mother superior, it's evident Ricky has been there, as the door has been cut open and kicked in. There is no way the other nun would have been able to freely enter the house without police escort, or even get out of the police car, as Ricky had not been located and apprehended. The house is a potential crime scene and she would not have been allowed in.

Mercury