Some horrifying disaster happens in New York, the subway tunnels are flooded. Fire crews need access to a locked/gated area, but your dynamo'ed electronic door lock is completely kaput.

The whole point of this critical infrastructure is that it be accessible in an emergency and have as few failure modes as possible. A mechanical lock has very few failure modes short of changing the laws of physics.

Fire crews have bolt cutters to handle the common case of a door with a small lock of any sort.

How reliable is that?