Many moons ago we had a fight in one of the off-post clubs that was notorious for drunken brawls. MP's and GP's go charging in and pretty much in front of G-d, MP's, GP's and everyone else, Subject 1 stabs Victim 1 with a good sized knife and then attempts to Exit Stage Left out a side door.
MP 1 pulls her sidearm and shoots Subject 1 right as he's exiting the door.
MP 1 is now in a world of *expletive deleted*it. Fleeing Felon rule. Even though he had just stabbed a person in cold blood in front of a metric buttload of witnesses, by attempting to flee he was no longer a threat to the MP's, GP's or the remaining drunken revelers.
Charges were filed against the MP and it goes to courts martial. Things look really bad for MP 1.
Fortunately she has a very good, very smart JAG officer.
During Courts Martial, said JAG officer points out that there were people outside the Exit Stage Left door, and that having just stabbed a person inside, it could be presumed that he posed a threat to those outside the door as he still had knife in hand (which he only dropped upon being shot).
MP 1 got very, very, very lucky that the court bought that defense, as she had no way of knowing that people were outside the door. (As pointed out by the prosecution.)
So what does that have to do with the situation here. Once miss crazy lady, backs out of the box and attempts to run, she is NO LONGER a threat to those officers. Yet, they fire at the fleeing vehicle. From back when I was taught/trained, this is VERY BAD KARMA. One simply does not shoot at fleeing vehicles. I'll point out again, that it's very, very, very hard to outrun Motorola. Especially in an urban area with as much Police presence as DC.
This was a public execution, pure and simple.