Police do not make death notifications over the phone. A detective would not simply hang up after doing so, they would arrange for the spouse to be interviewed.
As Brent is driving in "Philiadelphia", the low fuel icon lights up. The coolant gauge shown is in Celsius (metric), not Fahrenheit. The movie was filmed in Canada, and Canadian vehicles have gauges that read in metric units, so this reveals a clue as to where the movie was filmed.
Twice while at the office, the intercom is heard to say "Dr. Hest to Dr. Fisher's office". The first time Dr. Hest ignores it, and the second time he is talking to Dr. Fisher when the announcement is made.
The tiny completely wireless cameras used by Brent would not operate continuously for the amount of time shown, the batteries would die. Wireless cameras used in this type of setting are either much larger so as to contain a large battery, or only wireless in the respect at their signal (picture output) is wireless, but they still need a wired power supply to power the camera. As such, Brent would not have been able to spy on Casey and Jason as he was shown doing.
The bathroom window was large enough that Casey could have climbed out and escaped as Austin did.