I just started reading this thread, and I also assumed that you were talking about a highrise in the US, in which case, I was going to say that I am surprised that they ordered the entire 24-story building to be evacuated at once. However, now that you mention that it is in South America and the lack of escape routes and fire systems, that completely changes the situation.

In that case, I probably would not trust staying inside the building and would try and get to the ground floor as soon as possible. As others have pointed out, helicopter rescues are generally reserved for the movies, so don't think that you'll be rescued from the roof.

Although people may have been injured during the evacuation, I believe that in your case, the consequences of a large number of people staying inside the building could be far, far worse, so evacuating is still probably the better thing to do. Your situation reminds me of the terrible MGM Grand Hotel fire in Las Vegas in 1980 where a number of building codes and safety systems were not in place, and something like 85 people died and, I think, almost a thousand people were injured. That hotel was about 25-stories high, too. Therefore, I think the order to evacuate was the correct thing to do in your case.