Yeah, I didn't see any reason at all to taze him at that point, as he was just laying there not moving. It appears to be the strategy to allow him to close in on the guy.
Couple things. That's not a cop. He's a bounty hunter. Secondly, he didn't get tazed. The dude dry fired it as a tactic to further disarm the guy before going hands-on.
No video, but I once read a police report for an OWI stop where the driver answered the old "How many have you had?" (to which almost everyone in every police report I have ever read answers "a couple") by saying "15!". He then tripped in the roadway and fell into the ditch. I almost felt like rewarding him for his honesty somehow, but he definitely shouldn't have been driving.