Location: Usually below floors or inside walls of large structures and starships.

• Access:

  • Entered via narrow shafts behind panels or grates.

  • Opening these covers typically takes 2 or more Interact actions (popping fasteners, sliding heavy grates, undoing locks).

• Movement & space:

  • Most tunnels are crowded with machinery (pipes, conduits, coolant lines), so they are difficult terrain.

  • Some are so tight that Medium and larger creatures must Squeeze to move—slow, flat‑footed, and unable to act freely while doing so.