Cowering?
I have largely been in WildAlaska's camp in this case, and perhaps I am just taking his bait (clever fellow that he is), but I disagree with his choice of words.
From dictionary.com: cower: "verb (used without object)
to crouch, as in fear or shame."
If I was behind that counter, one assailant down by my defensive fire and the other fleeing, I would see remaining behind the counter as taking a positive tactical position, from which I could continue to assess and respond to both the down robber and the still-open door. That isn't the same as cowering "in fear or shame," that would be controlling a very bad situation to the best of my ability. Letting the robbers be in charge of the situation, including whether the innocents that work for me lived or died and whether I sent home to my wife that night standing up or in a bag, is cowering.
As I and others have expressed previously, the initial shoot appears to be justified, but the pharmacist caused himself legal and tactical and, IMHO, moral problems with his subsequent actions.
So, philosophically, I am opposed to cowering but in favor of good defensive tactics.