There is none. Just more noise in press than usual because AP was sitting in the building.
>Why would Israel bomb this building and tell people to evacuate?
Because Israel interested in taking out whatever Hamas physical assets there are in the building and not in killing civilians
> Is it normal for them to announce evacuation?
Yeap. Usually whoever occupies building get phone calls and SMSes hour or two upfront. This is usually followed by a "roof knocking" with specially developed munition that makes a lot of noise. Only after this bombing commences