The sensor of TOF camera is mainly for biometric, it can detect the distance of the person who stands in front of the camera. Currently, it limits to 1.5m for valid and identifiable target. No behavior will be detected if the target beyonds this distance.
Using TOF biometric technology, you can switch videos manually. If too many people stand within the distance of TOF camera, they will still be detected and the camera will get the most obvious features (largest face) to do the reconigiton and data collection.