IIRC (and I likely don't), what I read was some employee that saw people coming in and out with equipment, some of which he recognized as storage and other data-reading stuff, and a lot he didn't, and he was made VERY aware that he was not to talk about this, or even be in the area any longer or ever again, for any reason.

My recollection was that I did this reading in the mid 90's. But the wikipedia article for that room dates later, so this is the cause of my apprehension of placing the exact time.