Not me for once...
But I've been told similar versions of this story by two unrelated people that worked for the same bank so I think it may be true:
A large new data centre for a UK bank opened mid nineties just outside the Yorkshire town the bank was named for. It had new fangled doors with swipe cards to get through, though sometimes there was a 'push to exit' button at the side of a door to get it open.
A new cleaner was working at the site one evening and walked up to one of the secure doors. Looked at both sides for a card reader but didn't see one, though there was a big red button to one side.
Pushed the button to open the door but it was still locked? Apparently they got all the systems back up and running by close of business the next day!
One of the guys that told me the above also told me about the time they tested the fire suppression system for the archived paper storage at the same banks head office (a large office building in the middle of the town the bank is named for). They had installed a new halon suppression system in the basement, and the final test was of the extract to clear the halon if someone got caught in the area being suppressed (so they didn't suffocate). To do this they fill the area with smoke then turn on the extract to see how long it would take to get all the smoke out. They did this and the smoke cleared nice and quickly.
Walking out of the building, on the way to a liquid lunch after everything had gone well, there was lots of noise and fuss outside. It turned out the basements ventilation system was linked to the modern art statue in front of the offices, and for the last 10 minutes plumes of smoke had been poring out - obviously the fire brigade had been called.