Final answer:
The provided text does not explicitly describe the use of the PASS device, but from contextual knowledge, it is a safety device for firefighters that sounds an alarm if motionless, suggesting a firefighter may be in danger.
Step-by-step explanation:
The phrase that describes the real use of Personal Alert Safety System (PASS) devices by firefighters is not explicitly mentioned in the provided text. However, drawing from general firefighter knowledge, a PASS device is usually worn by firefighters entering a hazard area and is designed to emit a loud signal if the firefighter becomes stationary for a set period, indicating the possibility of a man down and the need for urgent rescue.
The references to firefighters searching and rescuing victims from burning buildings suggest a situation where a PASS device could be essential to firefighter safety, although the text does not detail the device's use explicitly.