For the most part (and I have a tough time saying it), I'm with Monger on this deal.
One of the benchmarks of any law enforcement agency's use of force policy should be something along the lines of a one-plus-one theory, which usually starts out with verbal or visual identification of an authority figure (meaning the announcement of "Police" or simply the display of a uniform and/or badge. Initially, those things did not exist in that poor woman's place, and the boyfriend is a hero for de-escalation. The Marshal, who swore an oath (some blabber about this constitution thingy) is sticking hard and fast to his guns that his stick/squad did everything by the number. Common egotistical cop response - assert your wrongness with even more conviction. The Marshal is lucky to be alive. That whole natural selection law thing skipped him over that night.
I'm not a LEO hater. I have several friends in LE that I either grew up with, or did LE work in the USAF with. That said, though, I'm not a badge licker either. Some of what I see or know about from LEO's is pure ego, and the escalation in militarization of our local PD's scares the snot out of me.