Don't know what was involved, I just caught this on the web.
Things I noticed:
1) He stopped the truck angled slightly away so that the truck bed covered the driver's door just enough to obscure his gun hand coming out
2) He committed to his action without any hesitation and moved very quickly. The Officers had almost no time to react before the shooting started.
3) He seemed to be at least somewhat experienced with a handgun. He took a two handed shooting stance and deliberately shot rounds at each of the Officers (see him switch targets left and right. He wasn't just spraying, he was aiming).
4) If he'd have left his truck in park, he might have gotten away at least for awhile.
5) The responding Officers returned fire very nicely. See the rear window shot out and you can see their shots tracking him down into the driver's area.
Last, I hope the injured Officer heals well and is ok.