When Ben is at the Police Station towards the end of the movie, he is handcuffed. Ben was brought in as a witness, not a suspect, nor was he arrested, therefore he would not be restrained with handcuffs.
When John is trying to revive Heather after her near-drowning, his hands are placed at the base of her neck when he's doing chest compressions. As a doctor, he would know that his hands needed to be lower down on her chest for the compressions to be effective.
The intercom near the doorway to Nathan's room is identical to the intercom near the doorway to Emms' room. They apparently used the same set for both rooms.