your assumption is that you would do it in one leap of faith and not staged. Short of a ferry like helicopter which could be loaded via a rear ramp up to the upper floor windows with very short blades which wouldn't fan the flames with down draft, there is not a great deal that would work successfully. I have seen the fall arrester used on radio masts above the 200 ft length using a steel wire which was permanently installed - i have no idea how that's supposed to work either. The backpack parachute is also a fail as you would most likely get the potential for 100+ people jumping at once in a small area, it would be like a turkey shoot in a barrel.