Mate,
You're wanting to be a radiographer... You aren't exactly Special Forces - DFR (and the wider ADF) have better things to do than listen to whining civvies. Put up (with the recruitment process) or shutup (about the recruitment process).
RSI is actually soon to be approved for IC level Para's in ASNSW, similar to AV and their MICA level skills.
But onto the question - not sure why you would do MBBS and work as a Para... Just do the Para degree, it's reasonably good. If you want to work as a GP, do Med and be a GP - the roles...