I believe What they are doing, is taking the talkgroup out of "repeat mode," so the other cars, and the news media can't hear the traffic they have to relay. However, this might be their terminology for going to a "private call." More research is needed to verify what exactly they are doing. That being said, I do know that sometimes on the old 453 MHz system, the dispatcher would leave their mics open and the patrol car's audio would pass directly through to their headsets, without the other cars being able to hear the message. Are you hearing something similar taking place when the car asks them to be taken out of "repeat mode?"
73's
Ron