definitely still do a biomed/eng or sci/eng double degree! don't limit your options, as you want to do med so badly in a few years and realise you haven't done biomed/sci, plus you seem to not be certain with what you want, so another area of science is good for you! and for the mind to expand;)
although you may find great interests in arts, the main problem with this i've discovered, as i also want to do so many art subjects (i could do an entire degree focused in arts and still want to do more subjects in many areas), is that most are things that are done out of interest and not for career advancement you possibly explore more and get more out of self-study.
as less fun as that sounds it's true, for example, to self-study a language can be far more efficient then the same thing for 2-3 years at uni, or studying & reading philosophical concepts of choice instead of having to write huge essays are some you may not find too interesting and don't want to do.
but you obviously cannot learn everything this way, but it is true for most interest-based arts subjects.