The shield used in this map is the Shadows of Evil shield. There are 3 parts.

Part 1 (Glass part): This part is located in the market area by generator 4. It is just to the right of the box when looking at it, on the ground.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1177706120

Part 2 (Eagle Part): This part is located in the Double Tap room close to generator 2. The part is located on boxes to the right of Double Tap. Although it looks like it, it can not be grabbed from the other side of the boxes.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1177706243

Part 3 (Fuel Tank): This is located in the Speed Cola room along the Main Street. When you enter the room, it is on the shelf located on your left.

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1177705965

To build the shield, you must bring it back to the room right after spawn. In the B23R room, there is a buildable table near the coast.

Hope this guide helps.