It is possible, as demonstrated by the Hong Kong Government Flying Service (Formally the Royal Hong Kong Auxiliary Air Force) in the 90's when one of the tower Blocks on Nathan Road caught fire during refurbishment. There were people in offices at the top who were lifted of the roof. But it was daylight and nowhere near the inferno seen in London. A very brave act though with the smoke etc and the need to put the winchman onto the roof!