From debug:
The hallucinoid is not moving only to adjacent nodes, because the game is after turn 20 already and cheating (aliens are in scout mode).
It can move to any node.
There are 175 nodes on the map.
In this situation, 76 nodes are compliant for moving.
Randomly a node with index=63 is picked... position [44, 54, 2]... which is below the barge.
Why are you even using all those empty levels on the bottom?