not disagreeing with you, but how about something similar to the systems used on oil rigs? they have a sort of mesh tunnel arrangement that drops down and you can slide down, even drop an unconscious body down, with relative safety.
although tbh it's kind of a pointless argument when we're talking about a situation where even basic fundamentals like fire alarms dont work, the building is too flammable and there's no sprinkler system installed.
edit: this:
Man that safety device is terrible. Did you see the problems the 3 of them had getting down?