Well, practically no skyscraper have those. And no chopper service is around to either spray water into those high fire truck-unreachable floors or to pick up people on top of the building. (Then again, symbolic skyscrapers usually doesn't allow people to go to the roof. The housing apartments in Hong Kong and I suppose Singapore(Please confirm/correct this guys) are the only ones I know where people get rescued b going to the roof.)
I hope people are considering such disasters in their construction.