10 Horror Movie Mistakes You Never Noticed Before

Before Lena Headey achieved icon status as Cersei Lannister on Game of Thrones, she was taking smaller roles in large movies and large roles in smaller movies. Bruce Hunt's monster feature The Cave is the latter, and sees Headey take on the role of Dr. Kathryn Jennings, a scientist helping lead the expedition to excavate the site of an abandoned 13th-century abbey in the Carpathian Mountains.

There are caves and underwater sequences aplenty, as the team becomes trapped and finds that they are not the only ones down there. But, despite going to great lengths to achieve believability in the mission, its participants and the technical accuracy of their undertaking, Hunt and his team managed to drop the ball in one key area.

In various scenes, the explorers can be seen using their Dive Rite H10-HID (high-intensity discharge) scuba lights outside the water. Unfortunately for the filmmakers, HID diving lights are specifically designed to use the water they are submerged in as a coolant, and so can't be activated for any sustained period above the surface, as they would overheat and fail.

So, sure, you may not have had the technical knowledge to notice this blunder the first time around, but now precisely what not to do if you ever find yourself trapped in an underground cave system with some ravenous winged mutants...