Can a patient be left unattended in the ambulance while double loading two patients in order to pick up or drop off the other patient?

No
A suitably qualified NEPT crew member must remain with the patient during the course of the transport, which is from receiving handover at the sending facility until handing over at the receiving facility

Source: Victorian NEPT Clinical Practice Protocols, 2023 Version, Page 101
This question is tagged as:
Double Load