A PCBU must consult, cooperate and coordinate with all others who hold a duty on the same matter so far as reasonably practicable (WHS Act s 46), exchanging information, finding out who is doing what and working together to eliminate or minimise risk. For example, when a supplier delivers goods, the PCBU should discuss with the supplier how goods will be handled, whether factors such as a flight of stairs with large boxes raise the risk, and what each will do to control injury risk to both sets of workers.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.