Extensive medical information is publicly available on websites like www.nhs.uk. So even if it wasn't literally trained on exam questions, it may have picked up

Extensive medical information is publicly available on websites like www.nhs.uk. So even if it wasn't literally trained on exam questions, it may have picked up substantially identical information elsewhere. Which is still a significant feat. But I doubt it's doing anything more than the sort of semantic lookup that is already well-known to be within its capabilities.