Perhaps the annoying beep was an alarm.
That annoying beep shouldn't have been the only alarm for such a valuable and irreplaceable repository of decades-long research. There should have been an alarm system that issues email alerts to a chain of individuals.
If that annoying beep was indeed an overtemp alarm, then damage was being done even before the janitor flipped the ill-fated switch, and nobody was around to act upon the alarm.