Part of the problem with the recent shooting of the kid with a toy gun was the cop's arriving in a car at full speed and stopping literally a few feet away from the kid. They then had no opportunity to assess the situation and instead pulled out the guns and shot him because they now where afraid they might get shot.
Since the park was empty it would have been far more appropriate to stop and assess from a distance.
So a (possibly) correct reaction to the circumstance they arrived at. But they arrived at that circumstance because of some very bad decisions made as they arrived.