Re: Critical Business
My brother did some work auditing (in the financial accountant sense) a rather well known large financial sector outfit with its own datacentre(s) - all 3 UK sites were below the water table & in flood risk areas (London, South Coast and another; I forget where). Access to the racks was through a secure airlock (vertical glass tube affair) with scales in the floor - if you weighed more on the way out than the way in it triggered an alarm. [Yes, I know, carry a bag of sand in under your jacket etc]
Unfortunately, the colleague accompanying my brother was quite large - so large in fact that he didn't fit in the tube. "No worries" said 'Security', and they opened up the delivery shutter at the other end of the room - which was quite literally big enough to drive a truck through.
(Of course, the actual audit/stocktake was laughable - all the units' ID stickers/serial numbers were either round the back, or obscured by the locks & cages everything was secured in; they just had to take the client's word for it that this row of identical black plates with flashing LEDs on it corresponded to that set of entries on the ledger)