You would have to ask who was killed. Was it just random Jane and John Doe going about their normal, boring lives, or was there someone in the crowd that was important? If they were important and in a dark futuristic setting,why were they unarmed, unguarded, and unarmored?
If it was just random people then she had no purpose for killing those particular people. If there was someone important, who were they and why did they need to be let go? Why was it done in a public environment?
If it was just the police looking to start stuff, such as a war against those using cybernetics, you wouldn't want one of them around you. You might hire one to do something dramatic, but you would want to remove them from play once they did their job.
having the officer in white show up behind her with a gun to her head is likely to have him or her do one of 2 things.
1. terminate the threat, which he was in position to do and appeared to have the right weapon due to their clearly confident posture.
or
2. Flip the agent.
Is the chick really an agent of a business, government, or individual? No idea, but having the individual turn around and join you is to treat them as an agent of sorts, which clearly it seems to be. Maybe the reason they were not using AP ammo is because they were really nothing more then a distraction for the person trained to handle that level of a threat.
Maybe she wanted to kill. Maybe she wanted to get some sort of payback for something, but did so without guidance. Maybe the cop that was behind her made her that offer to guide her towards the one she really wants to kill. if thats all she has left is to get even then to offer her that is to offer her the world, which is also a means of directing that anger and gear for one's own purpose.