When Stanley has Mallory chained by the ankle to the floor in the soundproof room, he tells he has to wash her clothes and asks her to take them off and put them in a plastic bag. She is wearing blue jeans. In the next scene, the jeans are in the bag. How did she get them off? They would still be connected to the chain.
In underwater scenes, marks are clearly visible on Mallory's face from a scuba mask. In no scene does Mallory have a scuba mask, so this is obviously from a mask she was wearing between takes.
When Mallory & Regan are thrown from the boat with their hands tied behind them, you can clearly see Regan put her hand out to steady herself as she "jumps in".
When Stanley went diving to visit his garden after he dumped Mallory there, he was placed under surveillance by a single police officer and his friends via a dummy Mallory but since he discovered the ruse, he managed to cover his tracks and escape undetected.
Regardless if it's a small town but for a crime as serious as a multiple murder case. Stanley would've been referred to by the police who would place him under surveillance within the lake. Whilst he returned back there, it would have been sealed off by a large team of police officers by the lake to make it difficult for Stanley to escape.
Regardless if it's a small town but for a crime as serious as a multiple murder case. Stanley would've been referred to by the police who would place him under surveillance within the lake. Whilst he returned back there, it would have been sealed off by a large team of police officers by the lake to make it difficult for Stanley to escape.