In the opening scene two cops find an empty car. One of them says that the keys are in the ignition, but the ignition keyhole on the side of the steering column is empty.
At approximately 8:56 into the show, there is a shot of the floor of the elevator in the squad room, when the doors open up you can see that the floor is continuous, revealing the the elevator is not real.
At the very end of the episode. There are multiple copies of the same licenses on the wall above the chained victim. In particular there are 4 copies of one woman's license.