Here is a link to an image of his helmet afterwards, and a story showing the officer with the head injury.
That was marksmanship by the perp. In the dark with officers shooting at him.
http://fox8.com/2016/06/12/police-helmet-saves-officers-life-in-tragic-orlando-shooting/
http://dailycaller.com/2016/06/13/you-can-now-see-the-police-officer-shot-in-the-head-saved-by-his-helmet-during-the-orlando-terrorist-attack/
More like a lucky shot. Every bullet ends up somewhere.
This murderer was no marksman.