[Carrie]

Sare it would depend on the buildings on Poydras street and the surrounding few streets. Did they have lights/power? If not, then that glowing 10th floor would have stuck out like a sore thumb and been suspicious.
Rarely can you can restore power to a single building and leave the buildings right next to it on both sides blacked out. The city's laid out in grids or lines and usually when one building has power, the other buildings on that grid/line have power.