Ghost: "Move 1 space through a Wall"; parallel Walls on separate Tiles considered one Wall?

For the purpose of the Ghost mask's ability "Move 1 space through a Wall", are two adjacent parallel Walls on separate Tiles considered one Wall?

Our assumption is no. We assume that both Walls are considered separate, so a Shining Gem would be required to pass through each; however, as the Ghost mask ability can only be used once per Turn, this would not be a valid Action.

What is the official ruling on this?

Thank you and be well!

- S.