So after evacuating the passengers onto the ramp area, how on earth do they "re-sterilize" the area from a security point of view? Or FOD for that matter?
They will, actually are at this point, be bused to a secure area and re screened, then allowed to go back to the terminals or leave. A FOD check will be performed by the ground personnel of the affected airlines. As for securing the area on the ramp where they were, the airport police and TSA agents will do that after all the civilians have left. This is SOP.
So for flights from Terminal Two and Three will be delayed for quite a while.