alreadytaken that is why I said work experience that provides the selectors with evidence that you have the qualities needed to do the job. That is a three step process, doing the job, gaining from it and articulating to the selectors what you gained from it that is relevant to your chances of being a successful doctor. So of a candidate thinks it is enough to have ticked the box marked "worked in an old people's home" without highlighting things they learnt that are relevant to medicine, eg empathy, appreciating the importance of giving people dignity in difficult situations, being prepared to cope with human mess, dealing with stressful situations, illness and even death, why it confirmed their wish to be a doctor, then it is just work experience as far as the selectors are concerned and no more relevant than retail. It is what you have gained from the work experience that strengthens an application not the tick boxing of doing stints in various healthcare settings. I gather it sometimes seems as if candidates have paraded through all these experiences without any of it touching the sides. And conceivably you might actually be able to highlight some aspects of retail experience that gave you relevant skills, especially people skills. In an interview some selectors, if they are any good, do drill down to specific incidents and how you handled them, hopefully in an encouraging way, to test whether you actually displayed the qualities they are looking for evidence of. In that context arrogance, a sense of entitlement, being overly coached, lack of initiative etc, all qualities I gather torpedo good applicants, will manifest themselves. So I would, from what I have heard, put it wider than displaying initiative, it is also about displaying flexibility, showing you have the personal qualities to care and to cope, at least potentially, and that you are receptive to learning and change. AND get the grades of course 
Of course you are right to highlight what a candidate will gain personally from experience in a healthcare setting in terms of being sure that medicine is the job for them, but that sadly isn't the whole story in terms of the relevance to the strength of their application.
The other point I was making though was that they are not impressed by impressive work experience in hospitals or deprived areas in the UK or overseas gained via connections, or at least no more impressed than the experience in local healthcare settings that anyone can access.