Some of the readings on this patient are odd, even considering his other circumstances. Besides being a rewarming emergency, there may be other emergency protocols required.
The second-in-command at this hospital is its personnel-coordinator, whose job is to know everything that all the employees at this hospital can do, including in some cases their hobbies. Besides readying the Complicated Patient Intake Room abutting the intensive care unit, she'll also dispatch orders to grab Merrin if she's on-shift within the hospital and reallocable, and call her at her home number if she's not. Merrin is the most likely person to have a random emergency cert not known to the hospital in advance, and there's efficiency gains from having one on-scene medic knowing multiple required protocols simultaneously.
(This does not, at this point, take the form of putting any explicit bets on the treatment results if Merrin rather than somebody else is the medic on-scene. Prediction markets are just starting to spin up for this patient; and they're based on guesses rather than knowledge about the patient's medical insurance, and what his insurance will pay to subsidize prediction markets, or how much his insurance will pay out per QALY saved (as determines the maximum expenditure on expensive treatment options). The hospital is obviously proceeding anyways on the assumption that he has at least standard insurance, pending identification; but it's also possible that his medical testament says to take zero chances on brain damage, and just suspend him straightaways. It's not easy to figure out how much you want to bet, in that sort of market, and it's mostly bots trading anyways this early on. So the admin just calls in Merrin, without betting on that as her own treatment subplan; nobody's really going to bet against her on that anyways.)