Neena wasn't completely unaware of her surroundings and even if she was waiting to take a shot at someone, she knew that in Gotham you needed to keep an eye (or an ear) out for anyone else there. She'd run into some trouble here before with that, mostly thugs or costumed assholes confusing her with someone else or thinking she was an easy target. It was always a mistake on their part, especially when she put a bullet right between their eyes or didn't even spare them that, instead breaking their neck in a specific place to leave them in a hospital bed for the rest of their life unable to use their limbs. So she knew when she was being stalked. It was something trained into her hard by her mentor.
"Depends on him," she replied without missing a beat, keeping her position though now a little more aware, "If you're here to try to stop me, we can take a rain check for another day. If you're here to ask me to join your circus, get lost." The man inside seemed to be talking heatedly. Probably haggling over a price for the goods which took some time in the end, which meant she might be here awhile. It was all about keeping her calm in the end, but his answer really made her choice between turning and shooting or leaving him be.
Chances are she would need to shoot. It was one of the downfalls of her profession. The high prices she charged wasn't for luxuries but to cover the cost of ammo that she needed. There was a bad feeling in the pit of her stomach telling her that this was one of those situations that wasn't going to end pretty.