The operation, which took place on Monday morning, involved removing the brickwork that had sealed the shelter's entrance since 1940. This opening confirmed the existence of a tunnel approximately 15 meters long, excavated directly into the live rock, with no additional galleries, confirming it was an unfinished construction.

The Bombers de la Generalitat used a drone to access the cavity's interior and check its condition. After analyzing existing documentation, images captured by the drone, and advice from the Collapsed Structures Group (GREC), it was decided not to enter physically and to reseal the entrance for safety.

These efforts are part of the preliminary actions for waterproofing the adjacent building and its surroundings. The presence of this shelter, dated 1937, was already known, and oral testimonies suggested a possible connection with the Teatre Metropol facilities, which prompted this exploration and documentation.

The deployment for this operation included municipal Heritage technicians, Tarragona Urban Guard agents, and five units from the Bombers de la Generalitat, including specialized drone units.