How to Build a Working Containment Door with Keycard Reader

Assemble the door frame

A Containment Door needs a solid frame before it will sit flush. Build the surrounding wall from Reinforced Wall A, Reinforced Wall B, or Reinforced Wall C, then place the Containment Door into the gap. If you want a smaller opening, use a Sliding Door instead and frame it with Wall A through Wall G. Reinforced Iron works as a reinforcing block around the frame if you want the door to read as a heavy bulkhead.

Wire up access control

Place a Keycard Reader on the wall next to the door. The reader is the access point, so it must face the side the player approaches from. Pair it with a Heavy Button for a manual override, or place a Heavy Button on the inside face so someone trapped in the cell can trigger the door. Use Opaque Trapdoor on side passages where you want a hatch that blocks sight. For a full airlock, install two Containment Doors back to back with a short corridor of Reinforced Wall between them, and put a Keycard Reader on each side. Test the setup by approaching the reader, then confirm the door opens and closes cleanly against the frame. If the door clips, replace the adjacent block with a matching Reinforced Wall slab or stair so the geometry lines up.