Huh... Y'know, on the one hand, I can see how Romy might have a fair case for firing on Batman in an objective sense. On the other hand, her behavior after the fact does not suggest to me "I was just doing my job" so much as "wtf did I just do?" I don't get the sense that Romy acted to neutralize a threat, I get the sense that her feelings about Batman momentarily overtook her.
Also, while hitting her and taking her gun is a big dick move, I can't honestly say I wouldn't be feeling petty if I'd just been fired on, especially if I had even a little reason to think that the cop who fired may have done so for personal rather than professional reasons.