What should crew members do when arming or disarming the doors?

When arming or disarming the doors, crew members should hold onto the red assist handle. This handle serves a critical function in the operation of the door's mechanical systems. When armed, the door is ready for emergency exit, and holding the handle ensures stability and control during this process. It prevents accidental operations and ensures that crew members can manage the door safely, maintaining situational awareness and control in a potentially emergency scenario.

The other options, while important in other contexts, do not directly pertain to the specific actions required for safely arming or disarming the doors. Checking passenger seatbelts, preparing emergency equipment, or notifying the captain are relevant to overall safety and protocol but do not focus on the physical operation of the door itself.