This method of blocking the zombie swarm's passage is the most common throughout Zombie Panic: Source. A player uses their push ability (holster and then secondary fire) to push an object in the way of the zombies as a method of stalling them. Nearly all physics props can be pushed, as long as it is not a part of the map's infrastructure (walls, doors, things that are linked to the ground). Sturdy barricades should be made of heavy and indestructible material, like a large iron table, file cabinets, and many others.