CT-TTB, The Traveller Book contains two adventures.
(Spoilers ahead for the adventure "Shadows.")
In "Shadows" there appears to be only one way built into the complex that one can descend/ascend: the "knobby cable" in locations 9+21. And we know the natives used it, because of the ascenders stored in location 21.
But ascending/descending that cable would seriously disturb the motion of the pendulum, which is presumably important? (See pattern inscribed below bob.) Is that really how the reptilians went up and down?
It seems really incongruous for a civilization that's mastered such technologies as stairs (see outside) and auto-targeting lasers (see premise of adventure) to make their priests shimmy up and down a cable, and in doing so make the cable do double duty.
Related: why the vertical shaft in locations 1+15? Did they somehow use that one to get up and down?