Explanation: When a mobile station hears an urgency signal (PAN-PAN), it is required to listen on that frequency for at least 5 minutes. This practice is a critical aspect of emergency communication procedures within amateur radio, derived from the spirit of FCC Part 97 rules concerning distress, urgency, and safety communications. The purpose of this listening period is to ensure that the mobile station does not interfere with critical follow-up communications related to the urgency call. It allows ample time for the originating station to convey its message, for other stations to acknowledge, or for emergency services to coordinate without disruption. Maintaining a clear channel for safety-of-life messages is paramount. Shorter periods (like 3 minutes) are generally insufficient, while 30 minutes, though not harmful, is not the specified minimum.