Even if the policeman knows that his shot has hit the criminal, the real question is whether the hit has rendered the criminal no longer dangerous. If the bad guy is still capable of shooting back, it is no time for the cop to stop firing, because his life is still in danger.
When there is more than one policeman on the scene, there is no reason for any of them to keep track of how often the others have fired. After it is all over, it may turn out that 30 or 40 shots were fired at the criminal.
But so what? It is very doubtful that the criminal has been hit 30 or 40 times.
Only part of the problem is that many people have no idea of the capabilities and limitations of different kinds of guns, much less how much difference it makes if the shooter is in the safety of a firing range or in the stress of a life and death battle. What is a bigger and wider problem is that too many people feel no hesitation to go spouting off about things they know nothing about.
People who have never run even a modest little business assert with great certainty and indignation that heads of multinational corporations are paid much more than they are worth. People who know nothing about medicine and nothing about economics unhesitatingly declare that pharmaceutical drugs cost too much.
Maybe all this is a product of the "self-esteem" taught in our schools, instead of the academic subjects in which American children trail children from other countries.