Plan of shopping center on page A6 of today's Washington Post shows a Fortune Chinese Restaurant right next to the two-tiered parking area in which the shooting occurred. The restaurant is on Rte. 50 (Arlington Blvd.). So apparently this means the driver went off on Rte. 50. I wonder if we can tell in which direction.
I heard eastbound on Route 50. Not sure if that was last night on the Cable News channel for Washington Metro area or if it was today on local AM radio news here in DC area today. From Seven Corners to cross the Potomac into DC would probably take 15 minutes or so at 9 PM. It isn't far, but fair number of traffic signals. Still wonder, though, whether two vehicles are involved and the van is parked nearby for a few hours for the hunt to fade away.
I've been in that shopping center many times, but not recently. Used to stop in it when I worked in DC and lived in Fairfax City and drove Route 50 for my commute.
Jack