I think it's difficult to say whether there was intent or not -- I don't see it as 'obviously' an accident.
But if it was an accident, why did he lie to dispatch, and attempt to cover up the shooting? That lie, on its own, should be considered a crime.
He surprised himself when the firearm discharged and that is clear in the video when his head jerked sideways and he stutter-stepped. I guess one could deduce he tripped/stumbled but it looks more like an interruption in pace due to the gun discharge surprising him.
I almost would bet money on the firearm he is carrying and I will leave it at that.
It appears in the video the firearm discharged unintentionally and thus he believed he hit nothing. His reaction is such that it was a non event as far as any assumed injury and why the driver was uncooperative.
Having said that, LEOs are not to have their sidearm out of the holster unless they see a need or a possible need to use it. Fleeing in a car/failure to yield in that condition, speeding, reckless driving, possible auto theft, etc., etc. are acceptable reason for him to have a gun out and ready.
LEs are trained to not have their finger on the trigger unless they are about to justifiably shoot.
Short of a malfunction of his service firearm, he had his finger on the trigger.
It will cost the Department civilly as it should, you can't recall a bullet, but I saw no evidence of an intent to shoot. Sloppy police gun handling all the way around.
Three lives ruined, with 2 killed. All because of poor choices.
Condolences to all involved. No reason on earth to be here tonight with 2 dead and an officer with a career ending traffic stop.