As someone who used (almost 10 years ago) to be involved with my state's emergency preparedness infrastructure (I worked in public health at the time), and who worked closely with law enforcement, firefighters, and paramedics in that capacity, I can answer your fourth question easily: officer safety comes first. That's official and unofficial policy of almost every PD in the nation. I'm not convinced it's the proper approach, and neither are a minority of LE I've spoke to about it, but there's a whole rationale behind why officer comes first.

I do complete share your concerns about police militarization and police brutality. I've actually seen it much, much closer up than vast majority of people here, and not in the capacity I refer to above; it's not pretty, yet it's very routine for most LE.