Groups comparison
Air ducts (Air vents) - 1993 to 2020
Involves the protagonist navigating through air ventilation ducts or similar structures not intended for human occupation for any purpose.
Tight corridors (Narrow tunnels) - 1993 to 2014
Includes any kind of narrow passageways, either natural or artificial, where one has so little space they can't go around anyone else in them without extreme discomfort. Commonly air ducts, maintenance shafts or trench tunnels.
Crawl tunnels[crawlspaces;crawl spaces] - 1996 to 2016
Very small tunnels one can't pass through while standing up and possibly not even while crouched, requiring either crawling with abdomen touching the ground or even changing one's size to accommodate.
Involves the protagonist navigating through air ventilation ducts or similar structures not intended for human occupation for any purpose.
Tight corridors (Narrow tunnels) - 1993 to 2014
Includes any kind of narrow passageways, either natural or artificial, where one has so little space they can't go around anyone else in them without extreme discomfort. Commonly air ducts, maintenance shafts or trench tunnels.
Crawl tunnels[crawlspaces;crawl spaces] - 1996 to 2016
Very small tunnels one can't pass through while standing up and possibly not even while crouched, requiring either crawling with abdomen touching the ground or even changing one's size to accommodate.
airducts
corridors
crawltunnels