For those thinking freezing could be an option... there's a fair bit more than just avoiding ice crystals.
Medical hypothermia in humans (which is just a few degrees colder) is bounded not really by not by time-cold but by restoring normal temperature too quickly. It turns out mitochondria generate a lot of free oxygen radicals when going hypoxic, and restoring oxygen quickly does the chemical damage that actually causes death - so they restore normal temps over a period of hours. I'd bet that's not the only metabolic cycle deranged by hypercooling.
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