IMO any pursuit by LEO FLEA or Leo Smith will as you state be interupted by some "lady" driving and getting "in the way" to allow the shooter to escape if this is an organized terrorist cell.
Possibility is high that the shooters E&E route has security on it to preclude such an attempt to capture. All what ifs aside I think it is goint to be futile to kill this guy as one more islamikazi will step up and take his place.
It is now an established fact that this method is NLT a car bomb in Israel for it's fear factor and disruption of day to day business as usual on the American Populace in the DC Metro Area........coming to a neighborhood near you soon no doubt......
Monkey See Monkey Do sort of thang !.
Ditto on the Raufaus HEI in the Barrett idea !!............:o) Stay Safe !
The origination of a rifle shot can be masked by using objects along the bullets path. Lining up a shot by design or fortune so that it passes a tree or building will cause an echo of the sonic wave from the projectile. This in combination with the original shot location and other objects passed would confuse any person unfortunate enough to be in the area. In an urban environment full of vehicles, houses, stores etc. determining the exact origination of a shot would be difficult.