
Why on earth would you put your secret lair in a public utility?
What happens if people need to use the shelter?
"But they don't have the codes, so they can't get in."
Now the best case scenario is that suddenly everyone is very suspicious of the bunker and why it is handled in such a strange way, and are EXTREMELY motivated to open the bunker and make it far more accessible.
The worst case scenario is that everyone fucking dies in a storm or a natural disaster.