Is this the same organization that initially purchased the 139s for EMS work without an air conditioning unit?
Regardless of that, CRM applies to both multi-crew and single pilot operations. There has to be a prioritization of tasks, even more so when flying single pilot in a fairly new type and in a very complex and potentially hostile environment.
It was only recently that the "C" in CRM changed from Cockpit to Crew.
On second thought, the Aussie Med types achieved what is regarded as a wet dream for the US EMS SLBs, being called "Flight Crews".

Boy, is THAT wrong or what?!