The taser is used the entire time he fails to comply with the deputy's orders to put his hands behind his back.
I've not seen the video; I'm just reading the above words.
So assuming that we have a case where the taser is actually effective, is the subject really expected to place his arms behind his back while being tasered?
If this is actually what happened, then there may be good reason for a massive lawsuit.
It would be the "Moth+Light" taser-till-dead deployment model. See [LINK].