It's always off-key, even after you think you're used to it. And it pulses slightly, irregularly, just enough to defeat your natural ability to block out background noise. No room in my apartment can keep it out. If there actually was a thief involved, we all would have cheerfully helped him steal as much as possible as quickly as possible, simply to spite the Alarm from Hell. The one person it doesn't seem to have attracted is anyone having anything to do with the Church.
Alarms are to notify the neighborhood that Something Bad Is Happening.
Notify them, then stop. Alarms are to notify the owners that Something Bad Is Happening. Notify them, preferably with electricity channeled directly to a delicate body part, then stop. Alarms are to notify the thief that they've been detected. Notify them, with a pleasant soprano voice, perhaps the computer from Star Trek.