not enough smerts to answer this myself;

massive gyroscopic battery in room full of wet cells and ther horridly toxic noxious shit.

Add earthquake. a sudden jolt with the kind of power tectonic shifts have to throw around, and the UPS room becomes a hazmat area? I can see the device failing safe by itself, or even by "lets hit it with a sledgehammer", but wherever theres a strong force, nature provides a stronger one. usually without warning at 4am.

or am I just being srsly Thick?

Paris, cos she knows what happens when big forces meet at 4am.