After a fire drill last month in which I learned that it takes more than five minutes to descend the one staircase in my office building from the sixth floor, I took a shopping trip to REI. I picked up a fifty meter hank of climbing rope, a kevlar rope guard, a harness, a carabiner and a figure eight for a little less than $200. It resides in a gym bag in the bottom of my filing cabinet.
Paranoia is just total awareness.
Semper Fidelis
My experience with descending a rope is one 200' drop. But I was with a group of scouts, 10-14 years. If fat 40-year olds and 10-year old boys can do it without serious training, certainly average office workers can handle it.