I have encountered quite a few. Quite a range of different careers/lifestyles/reasons for not going into medicine. People over think the whole non-medical careers thing. Your opinions are on par with any other graduate.
It's like saying - what can one do with an MPhys? Loads of things - teaching, academia, research, industry, self-employment, grad scheme at a supermarket, teach English in Thailand for a few years to 'find yourself'... The vast majority of graduates have to answer these questions - it's only the rare ones like us lucky medics who get to jump straight onto a ready made career ladder!
There are far more career pathways that don't require a specific degree than those like medicine that do. Even if they do, most people who can manage a medical degree will find it straightforward to put in a bit of extra study to bridge a gap, e.g. postgrad law qualification or something.In terms of specific examples... quite a few who went into 'proper science' research, a couple who did PhDs related to computing and now work in that field, some working in pharma - medical related but not clinical, teaching,...