At the end of the film, as Warwick stops John by the exit. He is wearing his jacket, but after he lets John leaves the parking garage, Warwick is shown without his jacket as he lifts his jacket from the floor of the booth, which is covering an unconscious booth attendant, and Warwick puts on the jacket.
When John is in the car in the parking garage, after Warwick lets him go he drives off. When the camera moves backward from the back of the car, you can see the crew shadow in the bottom left hand corner of the frame.
The postcard discussed was advised to be sent from the female friend whilst holidaying in Sydney, of post code 2000. However, upon further review of the postcard at the dinner table, it has a circular Post Shop lodgment stamp printed as 'The Glen 3150', which represents a specific Australia Post outlet situated in the suburb Glen Waverley, east of Melbourne. Sydney and Melbourne are about 1 hour 20 minutes flight from each other.
Warwick breaks a plate on the dinner table. After Warwick ties John up at the table with his hands behind his back, John finds one of the plate shards on the table. John takes the shard in his mouth and drops it in his chair. The camera cuts away for a few seconds and then the next time we see John he is using the shard to cut the rope that binds his hands behind his back. John would either have to stand up from the chair or bring his hands in front of him to get the shard from his chair into his hands. Not enough time passed for him to have done either of these things plus Warwick would have noticed.