Well, on the topic of the taser use. He appeared to have a hoodie on. I would bet my next paycheck that they didn't have the barbs in him. The one officer was drive stunning him and that should have worked….if the battery was still working, etc. especially in the neck. (this is science)
I know everyone wants to jump on the "he was on PCP" bandwagon….but electrical current and polarization and depolarization of muscle cells aren't effected by those type of drugs. It WILL make him bat shit crazy, make people eat peoples faces, etc…. Unless you get into a paralytic medication like used during sedation during a surgery, that affects the synapse.. its just affecting their mental status. (this is science)
Another thing was….if he was grabbing her hair, and they were utilizing the taser, it causes muscle contraction…. that might have had a bearing on him "turning loose" after the initial "grab" of the officer. (this is speculation)
Had I been on that scene, I agree with the asp use, breaking his forearm, or just peeling his fingers back, or a bullet in his head. I hear that does wonders for relaxing the central nervous system.

(this is science)