What action must be taken when the primary escapeway is blocked with water?

When the primary escapeway is blocked with water, the immediate priority must be the safety of all personnel in the area. Therefore, the correct action is to withdraw all personnel from that area without delay. This is critical to prevent potential drowning or other life-threatening situations that can arise from flooding in a mining environment.

Ensuring the safety of workers is paramount in emergency situations, and a prompt evacuation allows for a reevaluation of the conditions. The other options imply taking actions that could jeopardize the safety of individuals, such as attempting to drain the water or waiting for the water level to decline, both of which could expose personnel to unnecessary risk. Sending a team to investigate could also lead to further dangers if the conditions are unstable. Immediate withdrawal safeguards lives by ensuring no one is put in harm's way while attempting to assess or address the blockage.