The anti-gun nuts among us will be sure this is fiction. 60 years of police dramas and westerns have convinced too many Americans that a single shot often drops a person immediately. The suspect's ability to somehow keep shooting is chilling. So is the officer's quote of what the ER doctor said. It didn't occur to the surgeon the officer fired as many shots as he had to in order to stop the threat?
Limiting ammo capacity limits ability to respond to a threat: period.