Final answer:
Every staff member in a locked unit must have an emergency egress plan for emergencies.
Step-by-step explanation:
To ensure emergency egress in a locked unit, every staff member must have an emergency egress plan. This plan outlines the specific procedures and routes to follow in case of an emergency. Having a key to the unit and a personal identification badge may be important for accessing the locked unit, but they are not directly related to emergency egress. A map of the hospital can be useful for general navigation, but it does not specifically address emergency egress.