Would they have had a better chance at surviving if...
...if the police man hadn't gone around knocking on everyone's door and asked them to come downstairs? I know at that point no one fully understood the gravity of the situation, but in hindsight it sure would have been wiser to just tell everyone to barricade themselves in the apartments (like the alcoholic lawyer guy said he would).
It would have saved more of the apartment residents from running around and getting infected.