some points in my mind

1.comprehension:the grocery owner woudn't hear and understand the locksmith's words,and he's kinda a dork.thus after the bulgary of his grocery he took a gun to find the locksmith. a rational and normal brain is not alternative to form comprehension.
2.stupid dignity:humiliated by the seemingly-racist cop and bitched by his wife, the director stouts against the cop,which could induce a bullet in his head in that crucial situation. well, he is a lucky dog, for this cop is not racial-descrimination-intended.do not risk our life for stupid dignity.
3.do not jump the gun:what's really pathetic is the definite non-racist shot a black-american boy for not letting the boy finish his words.maybe this cop is kinda racist, for he has a stereotype thought that the boy was to reach a gun. anyway,do not act until we see clearly.
4.huamn nature: the movie aims to reveal the good side of the human,such as the seemingly-racist cop rescued the woman had been harassed by him,which is a mixed deed.the black robber released some trafficked southern-asian people instead of taking money from reselling them.what the movie intends to convey here is that good deeds are infectious.