That was a scary situation, you have an officer back-peddaling, drawing his weapon and going in circles, with civilians and another officer nearby. If he would have drawn and shot, instead of pointing at first... he would have been sending rounds in the general direction of 4 kids.
The thing that mitigates it somewhat is that the officer is mostly pointing his weapon down.
That dog didn't react to the taser the way you see humans do.
I've seen the YouTube video of a bull tazed with the large animal version and the bull went down like you see people do.
Police carry tasers that are supposed to be capable of putting down adult human males. That Rottwieller shook it off and kept going.