Let’s see. She gave fair warning. The trespassers/assailants decided to use lethal force (they started firing their firearms at her). She defended herself (flame shield) and then returned the use of lethal force (crispy critters!). She did not have a viable option to effect an arrest using less force; Each of the assailants posed a clear and present danger and she would need to incapacitate them all prior to arresting any. This can easily be argued as a justifiable use of lethal force under the “self-defense” clause.

To be fair, no one told these guys about any unchangeable plot points, except maybe the guys who sent them (You’ll be invisible, they won’t be able to hit you!), and those plot points just got changed on them.

In real life, barring reliable and clear prophecy, the only way to tell if a plot point is unchangeable is either to try to change it (success means it wasn’t unchangeable, after all; failure means maybe you didn’t choose the right way to change it) or to not try to change it, which doesn’t actually prove anything, but does establish that you’re not going to change it.

Long bacon.

“You can do this the easy way or the hard way.”

This is a trope in fiction and real life – where the character cannot accept an unchangeable plot point (“No, you are *not* going to be able to kill Dick Tracy.”), and hence cannot choose rationally between their options. A prominent feature of this irrationality is misplaced fear. The goons were afraid of their bosses – they should have been more afraid of fire girl.

The last king of Judah is reminded of an unchangeable plot point (The king of Babylon will conquer Judah), and given an explicit choice: surrender, pay taxes, and everyone lives – or the city is destroyed and your sons killed. Naturally, he choose the latter – for fear of the nobles of Judah (the other politicians both of the Surrender and FightToTheDeath party).