Harry's brain suggested that an obvious way to stop the Dementors from seeing Bellatrix was to make her stop existing, i.e., kill her. Harry congratulated his brain on thinking outside the box and told it to continue searching. Kill her and then bring her back, came the next suggestion. Use Frigideiro to cool Bellatrix down to the point where her brain activity stops, then warm her up afterward using Thermos, just like people who fall into very cold water can be successfully revived half-an-hour later without noticeable brain damage. Harry considered this. Bellatrix might not survive in her debilitated state. And it might not stop Death from seeing her. And he'd have trouble carrying a cold unconscious Bellatrix very far. And Harry couldn't remember the research on which exact body temperature was supposed to be nonfatal but temporarily-brain-halting.

from http://hpmor.com/chapter/56

Because the old ancient wizard has reason to believe souls exist, which means that while it's probably possible to keep Hermione's body functioning, there's "a burst of something... too vast to be understood" that's just gone missing.

Mind, that doesn't stop someone from figuring out a way anyway. Harry certainly plans to. It just makes things significantly more difficult.

Stuffed Into The Fridge, indeed.

I had assumed that such a, well, intense death scene would mean that her death was supposed to be really meaningful and so on ... but as I've been thinking about it, I've become increasingly certain that she'll be back.