Policy markets: Current top success-probability is if they don't rewarm the patient at all, right now. Explanation-summary: it preserves option-value if anybody digs up a further injury that'd potentially occur on unguarded rewarming of the patient's brain from 20C-cold to a more standard 28C-cold.
The market's success probability dips suddenly even as Merrin watches, some unknown trading entity placing a more pessimistic bet, but doesn't drop to the point where it goes underneath the success probability if they start rewarming the patient to a higher cold temperature right now.
...the markets haven't actually updated yet with a protocol telling her how to semi-stabilize a patient at this temperature, but presumably that will be on the way very soon?