That happened once on my first day of middle school apperently a water leak in the ceiling spilled onto the computer that controls the bell but instead of a phone ring sound it was like a siren from both a police car and garbage truck. It was weired amd it didnt sound like the fire alarm
My senior year of high school our school bell system was having technical difficulties and a loud noise came thru and then our principal made a announcement that our intercom system was down no bell tones in between classes until itbwas repaired
My former high school I went to had this malfunction everyday when I would do daily announcements my senior year but that alarm type sound is actually our tornado siren warning for tornado drills or the real thing because the 4 digit code for the PA system to work was almost the same as the tornado alert alarm the 4 numbers for PA was 4342 and the tornado alarm 4341 but these codes change every school year