I have a friend that has had a few altercations with the police and it takes a good few of them and one hell of a commotion to get him to the floor. Without that taser it would have taken both of them to try to floor him and then that could have gone really bad especialy with a child involved.
This is what I don't think some people appreciate - though they probably should have waited for more police but then I don't know the real world situation in that regard. If it needed both officers to deal with the guy the child could have come to harm. Tasing him was the safest option for everyone involved as he wasn't cooperating.