Factual error: Jeff, being a medical student doesn't really seem to know how to make sure infection doesn't occur. In the scenes where he is cutting out parts of plant from Stacy's body he pours alcohol on her body before cutting it. This is totally useless as he doesn't put alcohol on his hands, the knife or inside the open wound after he cuts it. Infection as almost certain to happen because of this. This is practically impossible to not know by a medical student.
Continuity mistake: In the scene where Stacy is lowered into the temple to check on Mathias, the first time we see the crank there are about five loops of rope left on the wheel. After a quick shot of Stacy, the camera goes back to the crank and there are now about twelve loops of rope on the wheel, even though she is being lowered not raised.