Begin with the beginning. The 911 call. The officer is basing his or her first impressions and tactics and strategies on the impressions and information given by the dispatcher who reads only what was placed in the call by the call taker. What happened prior to the video could be a range of reasons for the police to make a warrant less entry. 4th amendment protects your right only as long as someone in that residence is not in imminent fear of great bodily harm or death. If the dispatcher is on the phone with someone in the residence and gets enough information to convey that threat then yes, LEO will make entry. If the LEO hears sounds coming from inside that indicates an assault in progress they will make entry. It falls under probable cause. The LEO will still have to articulate that in front of a judge.
A five year old me wanted to become a LEO and so schooled myself and trained and upon hitting 21 I started applying. Never had been bullied in class and at 5'5" and 110 lbs, I certainly didn't have a bully bone in my body. I don't do it for the money. I don't hold rank. There is no brass on my collar. I have a ticket book in my car and for the last two years I have not written out of it. I am in it solely for the fulfillment I get from helping people. I enjoy my job. Hell, last Christmas, I brought two homeless children to my house instead of letting DSS keep them. My Sgt. was displeased but I gave those girls a good Christmas. They were delighted to simply get a toothbrush. I didn't get a thing from it but the sense of "rightness".
There are good LEOs and bad LEOs. There are good teachers and bad teachers. You can't point to the Catholic Church and claim THEY hold the most Puritan people. With any job that wields a power over a people comes a corruption. LEOs, teachers, preachers, POTUS. I mean really, who has the ability to toss stones?
