When the killer 1st enter the file room,the lamp and binder book on the table is placed deeper in on the table, but later during the fire and fist fight, these items are at the table edge.
When the killer 1st picked up Tom's ATT iphone and seen the video of him killing Roger, the time was displayed was 10:36, but when Tom and Emmerich was trap in the file room and the killer displayed the text messages to Anna, the time displayed on Tom's phone was 3:43. It's very unlikely they was a time lapses of 5 plus hours.
(at around 57 mins) When Emmert is confronting the killer, his gunshot wound in on left arm, then in the ne wound is on the right arm (killer picking Emmert up from floor), then when Emmert stands, camera angle changes and gunshot wound is back on left arm.
When the movie 1st starts, we see Tom entering the elevator and pushing floor #34, but if you follow his access_card it shows floor #29.
Tom is unable to call 911 due to phone lock; however every phone has an option to dial 911 even if the phone is locked.
Tom updates his card and then resets all cards, it should reset his card too. He should have updated his card after the reset,
When Tom starts his camera the time on his phone is 9:35 with a battery o more than 50% and when he gets his phone back the time is 10:33 and the battery is not even enough to call 911. iphone's battery usually doesn't drain so fast during recording.
When the killer gets Tom's phone it shows the video start from where the killer starts choking with the phone wire, whereas it should have started when Tom puts his phone to record about an hour before that.
When the killer shoots Janine after she becomes suspicious of him, his gun emits a cloud of smoke. However, smokeless powder has been used in ammunition since the early 20th century.
When the killer strangles Roger and Roger is laying dead in a chair after Tom runs into the closet, you can clearly see Roger blink his eyes although being dead.