The Police are there to just be shot at. And let the Assholes drive off and live to see another day so that may rape, torture and murder their hostage than Rob another Bank and repeat when the urge hits them.
Ed
Yeah right! So the cops killed the hostage to deny the robbers the pleasure of torturing and raping the woman.
The police have choppers, and can still persue at at safe enough distance. Thus keeping the hostages safe as possible.