Final answer:
The security officer should assess the fire and communicate with superiors to receive instructions.
Step-by-step explanation:
After calling the Fire department from a street box to report a fire, the security officer should then assess the fire and situations and report conditions to superiors to receive instructions. This can be done using two-way radios. It is important for the security officer to communicate with superiors to ensure that all necessary information about the fire is relayed accurately and quickly. Additionally, the security officer should follow any instructions given by superiors to coordinate efforts and ensure a safe and effective response to the fire.