Simon, Police training always concentrate on "overkill" because of the need of "situation control". That's why you see more cops than suspects at any car stop. Taser, baton and pepper spray etc are usually used on unarmed suspects. Even with all those gears, I was hurt numerous times when making arrests in the past. Domestic violence is very dangerous and volatile. Police presence further aggravated the suspect to a boiling point. That's why we were trained to park our patrol car at least two houses away from the incident to avoid detection and to access the situation before going in. Police work is tough and dangerous and I advise not to make any judgment if you are not there at the scene.