Unless times have changed since my time there, the percentage of critical must get to Perth asap / Med 1 is small.
With the centralisation of medical care in Perth (due to cost of machines that go bing) and the dearth of specialists in regional centres, all and sundry ended up in Perth. For a Kimberley based PC12, that means that the aircraft and crew probably can't make it back home at the end of the shift, meaning that the Meeka / Headland crew need to cover the Kimberley on the next shift....and the snowball gets bigger.
By fetching the patients from kickatinalong and blackstumpalong in the PC12, and bringing them to Broome, then the PC24 Broome crew can nip down to Perth and back and the BRM PC12 crew will be home in time for an early dinner. And of course it has the gravel approval for those times when needed when direct PH is preferable from kickatinalong.