It is just that simple. If they fire the first shot, they are the cause of the situation going south quickly. There is a reason why martial artist are considered deadly weapons and held responsible if someone gets hurt. Cops are no different, yet they get away with it simply because they wear a badge. Deadly force should only be a last resort, not a first response. People need to know the cops are there, and why they are there, before they can be expected to cooperate period. If people don't know what is going on, you never know what to expect. And pointing a gun at them until they do is playing jeopardy with their well being.
The whole notion of barge in, capture, and ask questions later is all wrong. They're not even looking for a peaceful outcome that way. They only prove just how big they're head is, behind that badge. People should be given the opportunity to come out peacefully, especially if the charges against them are based on the word of a single caller.