Though the "environmental suit" is a fictional invention for the show, it is inconsistent in its application. At one point the helmet becomes stuck with the internal oxygen supply running low, and neither a drill or a blunt instrument can crack it. Yet elsewhere on the suit is cut with a simple scalpel, exposing skin. Either the entire suit is airtight or none of it is; it would be impossible for only the helmet to seal around someone's neck without cutting off their ability to breathe.
Sian tells Darby she walked on the dark side of the moon. There is no dark side of the moon.
When Darby and Sian get in the car in the snowstorm, it is a newer model Volvo XC90. After it rolls down the hill it is a first gen model.
Darby and Sian search the car for a key. However the key fob works no matter where it is in the car. As long as it was somewhere in the cabin, the car should have started.