Ghost Mode Idea

The Global Risk should have some type of device that allows them to see the Ghosts that are in a certain room with them on the radar. Say for example I am in B site and I use the device I can only see the ghosts that are in B site. The device can only be used once every round though so the Global Risk players have to use it wisely. Theres a downside though, the Global Risk only see the Ghosts on the Radar for 30 seconds, or less. So tell me what you think is a good idea. Give me any suggestions you have please! :-D