I asked you to cite the particulars because I imagine the legitimacy of grammatical rule breaking would depend on the details.
Elmore Leonard sometimes took liberties with grammar in the interest of speeding the story along, and I never heard any complaints about him.
Elmore’s exceptions to the rules were of a completely different nature. He was a master of the English language, both written and—more important—as spoken. He was the most literary of all the crime/thriller writers.
I can’t bear to give his books away. They are all lined up on a convenient shelf and I read them when I want to be amused and amazed all over again and am never disappointed.