Which item is essential for the EFB fire drill when safe to do so?

In the context of the EFB (Electronic Flight Bag) fire drill, placing the EFB into a metal bar box is a crucial step when it is safe to do so. This action helps to contain and minimize the potential spread of fire from the device while providing protection against any further flame development. Metal containers are specifically designed for such scenarios as they can withstand high temperatures and prevent flammable materials from igniting.

For the scenarios involving the other choices, removing the EFB immediately from the area could potentially spread the fire and compromise safety if not done carefully. Using water to extinguish the fire is not appropriate for electronic fires, as it can lead to electric shock or further complications. Turning off all electronics is important in some contexts but does not specifically address the direct action needed during the fire drill concerning the EFB. Thus, utilizing a metal bar box is the recommended, most effective response during such a drill when conditions allow for it.