Doing another degree first when your plan is to do medicine anyway is a huge waste of time and money. Also, medicine for graduates (either standard entry medicine or graduate entry medicine) is considerably more competitive than for school leavers. Just forget about Oxford and apply to medicine if your aim is to be a doctor. It would be truly absurd to apply to another degree at Oxford, to do medicine later, just so you can say you went to Oxford. Moreover, it will actually hurt your chances of ultimately qualifying as a doctor because as noted, for graduates medicine is much more competitive. Just apply to medical schools that don't emphasise GCSEs as much.
Doing medicine at Oxford makes no difference whatsoever compared to doing it anywhere else. Likewise doing your first degree at Oxford then medicine (anywhere) makes no difference in your career as a doctor. Medical recruitment does not consider where you went to medical school - it is not factored into the algorithm for foundation post allocation, and for specialty recruitment they are barred from discriminating against applicants (positively or negatively) based on where they did medicine and usually your application is processed "blind" so that the people interviewing you and/or making the decision do not know where you went to medical school anyway.
Your repeated posts on this matter will not change the answer you will get on this. Accept that you need to make a decision between medicine and Oxbridge at this point - noting as above that going to Oxbridge will make no direct difference in a medical career whatsoever. Don't do something else in order to do medicine later. Also Oxford considers GCSEs for all courses (to varying extends) and biomedical science is extremely competitive there as well due to it being such a small course. Additionally Oxford BMS does not consider applicants with a medicine personal statement.
Also, repeatedly making threads which are more or less thinly veiled ways to get people to validate your prioritising Oxbridge over medicine, but still wanting to do medicine, is not constructive for anyone involved and wastes peoples time answering you in good faith when if you don't get the answer you want evidently you will just make a new, slightly different thread with the same ultimate goal.