The woman who comes in to take over looks to be in her early thirties, as is plausibly where you'd find the optimal combination of stamina, reflexes, and having done a whole lot of weird sims and even gotten a pretty large chunk of actual weird medical experience.
(Rank five medtech at Default Hospital. Merrin is unlikely to recognize her from Exception Handling scenario TV; the Medtech sticks to real patients for the most part. Merrin might recognize the Medtech if Merrin is familiar with the most famous medical oppers on the planet as such.)