I have seen several people point out that the victim shooter in this situation could be held liable if he would have hit anybody other than the shooter in the vehicle or an innocent bystander outside.
While it is true that we are responsible for the rounds that we fire and the fundamental rules of firearms safety still apply in a gunfight, let me attempt to shed some light on a procedure of law that may not be apparent to some of you. I have testified as an expert witness in more than one case involving similar situations, only in which an "innocent" bystander or property was actually hurt/damaged by the victim's shots.
If a person shoots at an attacker in self defense but inadvertantly strikes an uninvolved friend of the attacker or even an innocent bystander, it can be shown by a mere preponderence of the evidence (more than 50%) that but for the actions of the attacker, the 3rd party would not have been injured. By that argument, it is the original attacker, and not the defender, that is responsible for the injuries sustained to the 3rd party, regardless of whether it was the attacker's shots or the victim's shots that inflicted the injury.
The accepted reasoning that the courts must consider is whether or not the injury would have occured if the victim had not been forced into action. Arguably, the victim would not be shooting their weapon if that action had not been preceded by a criminal attack. Therefore, the attacker becomes responsible for the outcome, not the defender.
A victim cannot be held criminally liable for actions that were taken in defense of themselves and in many cases, the defense of others. Don't get me wrong, the courts have tried (and probably succeeded) more than once but that is where I (or someone like me) should be called in.
The distinction in whether the victim is held liable for their rounds striking someone other than the intended target are in relation to the "reasonableness" of their actions and/or whether they acted in a "reckless" manner. Remember, while the courts (or victim attorney) only have to show by a preponderence of the evidence (more than 50%) that the attacker is responsible for the injury of the 3rd party they would have to show that the victim's actions were reckless or unreasonable "beyond a reasonable doubt" in order to hold them liable, and that is a much larger burden of proof.
If the actions of the victim were not "reckless" or "unreasonable," than the original attacker is responsible for any tertiary damages, including the death of an innocent from a bullet fired by the victim defender. The attacker could actually be charged with manslaughter even though the victim fired the fatal round. Difficult to follow, I know, but it makes sense if you think about it.
I do not have enough information to make a judgment call about this particular situation, and in any event I would not want the personal burden of a round I fired striking an innocent regardless of who was criminally/civilly found to be liable.
What I can say is this. Time and time again it has been found reasonable to return fire at the "general occupants" of a vehicle from which you received fire. I put "general occupants" in quotes because this is the exact term that was a point of contention in a case I reviewed and those were the investigating detective's words used in the report. The outcome was this. While they may later be found to have not been involved, it is reasonable for the victim to assume that all of the occupants of the vehicle either knew what was about to occur (the drive-by), participated in the event, or were willingly present non-actors. Otherwise, unless being held against their will (which the victim would have no reason or responsibility to assume) they would not be in the vehicle. The victim defender incurred no criminal liability.
Further, just because an attacker has stopped firing (or their vehicle passed) does not mean you must stop firing at the threat that was present 1/2 second ago. Don't get me wrong, I understand the philosophy of "imminent danger" but it has also been consistenly ruled that the danger is "continually present" beyond the immediate shots fired. No, that does not mean you can chase them down and continually fire at them or go get them later. However, this concept has application in an instance such as a police officer walking up to a car, getting shot at, but not being able to return fire until he draws his weapon, by which time the vehicle is already driving away. The officer is still justified in firing at the fleeing vehicle due to the "continually present" nature of the aggression.
The same is true for an armed robbery. A store clerk, having been robbed at gunpoint, could conceivably chase the suspect out of the store and shoot the robber as they tried to get into the vehicle. The "imminent" threat is over but the incident has not yet concluded.
Having said all of this, please don't think that I endorse such actions. I am simply pointing out some rules of law/procedures.
One thing I do find interesting is that in almost every case that comes up on here the same people say, "He wasn't justified.... it wasn't clear enough.... the target was moving..... there could be bystanders.... he can't guarantee a perfect hit...." and so on. Let me tell you something folks, there is no such thing as a perfect shooting but I hope that this won't prevent you from taking appropriate action when the situation calls for it.
If you will only present and apply deadly force when the target is stationary, there are no innocents around, the light is perfect, the background is solid, and you are taking incoming rounds (because by some of your arguments if you're not the threat is over), leave your gun in the safe and only take it out when you go to the range. You will never have an opportunity to use it on the streets.
Alright, that was long enough. Let the flames begin. Just understand, I get paid to testify on the very basis of what I have just explained.
P.S. Yes, I know that laws vary greatly from state to state. I take that into account when I testify on such matters but I don't have to here so this is not legal advice. Your local laws take precedent.