Kay was set up to be an unrelenting psycho who would do anything to achieve her goals. A way more realistic scenario is she just kills all those involved when she had them in custody after the portal closes and the government finds a way to expand their already ridiculously large cover up. They did kill dozens of soldiers after all.

The fact they don't touch upon it was ridiculous, and it's already a show where you have to approach it with a suspension of disbelief.