Forget about too slow coming down.
Forget about the fact that the building is 23 storeys high.
Forget about the fact that the slant on the building is 45 degrees
Forget about the fact the the surface isn't flat. It has ridges where all the panes meet the metal work so it would be bumpy as hell.
Forget about the fact that they aren't wearing helmets!!
Forget about the fact that Jackie Chan has slid down this building on his ass
But dont forget about the fact that at the end of the slope...............it has a 3 storey drop onto concrete.
Fake!!!