When the fellow traveler is calling the police from the baggage claim, he brushes against the post and it can be seen to move.
When the protagonist is led outside "for some air," she's carrying some small items in her hands, But neither the young man nor she is carrying her luggage before she is forcibly put into the police car. Her luggage is nowhere in sight.
Paul and Millicent's first conversation lasts for almost 3 minutes, yet the clock on the wall behind them remains at 2:15.
Paul looks down for s few seconds and when he looks up his bag is gone and his duplicate is running out the door empty handed. There wasn't enough time for the bag to be taken anywhere or hidden, so the duplicate should have had it.