Maybe it's naive on my part but I would have assumed a 14 year veteran who served four tours of duty might be able to assess that trying to break through a guarded door while the people inside have their guns pointed at you is a relatively dangerous situation.
Her social media is still visible. Here’s a tame, yet representative, post...
She definitely wasn’t inhabiting the same reality the majority of us are.
Her radicalization was clearly evident.
In a more abstract sense, I think Trumpism is all about cognitive dissonances. There are things you want to believe, maybe because they are more comfortable to you, (e. g. "covid isn't that bad, I can still go out", "climate change isn't real, I don't need to change my lifestyle", "the immigrants are to blame for my unemployment, not me, I don't need to change and am fine the way I am") and there are facts which might contradict those views (science primarily). Then you can either adapt your opinion and accept the uncomfortable or build constructs in your head (conspiracy theories) that delegitimize the unpleasant truths. However, Trump tells people what they want to hear and it makes it easier for them to blend out facts and logic. He gives them easy ways out to live how they want to live against better knowledge and they give in to their basic instincts (blaming others, etc.) instead of using their brains.
I think we're beginning to witness the pinnacle of this mindset. They were "protesting" in their echo chamber, probably told themselves on and on again that they're the people, the silent majority, that cops and military are on their side and that nothing would harm them. In the same way, they convince themselves that semiautomatic rifles and some improvised gun range shooting prepares them for a battle with trained forces.
Thing is, in the end the fate of this woman might be symbolic for what's coming. Trump will not leave it at that, he'll escalate things further. The institutions have been really inconsequential with Trump supporters' wrong doings in the past and that has probably only confirmed their illusion of invincinbility. But if things continue like this, at some point the military has to intervene. Just like this woman probably didn't even entertain the thought that she might die if she ignores the warnings of the police, they won't know what they got themselves into until it's too late.