Character mistake: Laura is on the floor, screaming and exhibiting bizarre behaviour, so Dr. Rose Cotter goes to the wall phone to call for help. Instead of maintaining observation and continuing an evaluation of Laura, the psychiatrist faces the wall while making the call and even stares at the wall for a couple of seconds after hanging up. A patient's body language can/do help make a diagnosis, so the psychiatrist should keep her eyes on Laura. (00:11:20)
Character mistake: The prosecuting attorney told William, "In the interests of getting this thug [Danny] off the streets as soon as possible, his attorney has agreed to plead guilty to assaulting an officer, possession with the intent to distribute, and resisting arrest, and that's all in addition to his parole violations. We're looking at five to seven [years in prison]." The parole violations alone are sufficient to get Danny off the streets immediately. (00:09:34)
Character mistake: We see the lead driving on the motorway to get to the cottage. She leaves at junction 6 for Princes Risborough. Which means she is on the M40 that goes to Birmingham. When she arrives the host asks about the drive down and mentions the M4. This is a different road entirely, that goes to Swansea.
Character mistake: The Predator is jumping through trees, then landing in a creek, splashing in the water. Its cloak barely flashes for a moment, then it can walk through the water still cloaked. This is a prequel to the other Predator movies, where it is already established that with their cloaking technology, even in the future, walking in water or getting wet disrupts the cloak and it malfunctions. (00:37:10)
Character mistake: Nolan said, "Everybody knows that no sharks swim in freshwater" and Spencer said, "They don't come into freshwater", but there are freshwater sharks (e.g, river sharks) and bull sharks (not true freshwater sharks) can survive in saltwater or freshwater. Jacob Harper (National Aquarium) pointed out eyewitness accounts of sharks swimming up the Mississippi River and "bull sharks have kidneys that recycle salt" but did not mention the glands near their tails that help keep salt in their bodies. (00:08:08 - 00:29:50)
Character mistake: Doreen/Mom told Rose she'd be back from the store "in a jiffy." Rose asked, "How long is a 'jiffy'?" and Doreen replied "in about an hour." "Jiffy" typically means VERY fast (perhaps as short as a nanosecond) and, even if people have different perceptions of how much time a "jiffy" is, an hour is excessive by general standards and does not reflect its true meaning. (00:32:50)