After playing around with a simple airport without any pathing errors everything has broken spectacularly the moment I added an underground floor; even between zones directly adjacent on the same level and I am coming up short as to why.
This employee is for some reason trying to use the bathroom in the upper left corner of the image. The employee is in a staff area and the bathroom is in the a secure zone.
The security checkpoint between the staff area and the secure zone is set to allow staff only.
And here is the pathing analysis tool showing that the path it should be able to take.
Affected employees typically freeze and do nothing at all, and the airport is now mostly paralysed.
Ideally there’s a simple solution to this and if there is, that will hopefully solve the issues I have between levels as well…