Takes me back
I used to work at the NIMR in Mill Hill before some silly soul decided a large greenfield site wasn't a patch on a skyscraper in the centre of London and it became The Crick Institute. I can imagine how that boffin missed the stairs being removed.
I used to do make transgenic mice, the animal facility was entirely windowless, anything could happen while you were over there.
During my PhD I spent a lot of time in the basement. My mice were down there, the electron microscope suite including the room where we cut ultrathin sections on ultramicrotomes. There was even a cryo-ultramicrotome. People would cut frozen ultrathins then label things with antibody's tagged with tiny bits of gold big enough to be seen in the electron microscope (gold looks dark in the EM).
I was never down there in an earthquake or at least not a significant one. I was just up in the lab one Saturday. It's an 'interesting' experience being surrounded by chemicals, solvents, biological agents, the radiolabelled stuff behind the lead bricks in the fume cupboard in an old stone building with room to fall into the basement and have the floors above come down on you.