I lived in Cairo 3 years. This is the epitome of a SHTF situation for an expat in Cairo, Libya, or anywhere in the mid-east.
This is the time to get the emergency cash out of the floor safe, and distribute travel tickets to all your staff, and haul ass out of there. By Friday after prayers, the place will be an inferno. All American interests will be attacked.
Do not wait for the US govt to tell you to act. It will be too late. They already sacrificed Ambassador Stevens in cold blood.
Meanwhile, the travel group Abercrombie & Kent is giving 50% discounts of their tours to Egypt. At least when I looked last week. Might be 75% off by now!
If they have not done it already, it’s time for Israel to beef up their security at their boarder with Eygpt, and call on the military for stand by.