I expected some redemption carried over from a poor article, but somehow this is even sloppier that it was actually infuriating to read. What you set out to build a setting amounted to criminal levels of spoonfeeding:
Below those descriptive words were meant to tell the reader what the thing inside the cell was capable of.
"Who are you?" One of the people in the camp inquired, observing the mechanical cyborg and the bloodstain from her most recent victim.
As if we forgot she killed a man a paragraph ago.
in an attempt to prevent the mechanical girl's entrance.
Their action already demonstrated this. And worst of all:
Her victim carried a wooden coin depicting an odd-looking tree with two people praying to it on either side and the words "Descendants of Yggdrasil" on the back. He also had a map of this entire facility on him, but with various markings signaling where she could easily enter and exit the facility without being detected.
Really??? This is some movie title-drop shenanigans; it's actually insulting the reader's intelligence like we can't piece this together from the moment it said tree.
It baffles me that 439 was housed in Site-031-2, a Natural Bioclimate containment site, when its main ability is regeneration by contact with biological matter; why in containment's name do you make their job doubly hard? As cool as a 550 breach may be to write about, it doesn't justify the Authority accommodating it with a potentially VERY EASY breach. In fact, I was confused the moment I read Site-031-2 that I assumed you added it willy nilly but no, this straight up ignores common sense as an excuse to write this specific scenario.
The conclusion isn't anything groundbreaking either, and barely sets anything up for a, frankly, boring conclusion. I find it funny how this ended up neutralizing it, which is the only good thing I can say about this tale.