your questions regarding the game rules (improving the interpretation).

From my point of view, this is a violation. Here are excerpts from the rules.
First, the rules governing transitions between zones:

- a) From the rules applicable to all templates:
"2.6. Transitions between zones.
By "a defined passage between zones" on the generated game map, we mean the space between obstacles forming the boundaries of the zones, through which a hero can pass into an adjacent zone. In a real game situation, there may be several such passages, even if the template diagram indicates that there is only one passage.
On all templates, except for XL+U size templates:
2.6.1. To pass from one zone to another through a defined passage, it is necessary to eliminate the guard of that passage. If there are several guards on the passage, it is sufficient to destroy any one of them."
- b) From the rules specifically for Jebus Cross: "Additional rules for transitions between zones:
- In order to exit your zone into the central treasure (zone 5), and also to pass from the central treasure into other zones, it is necessary to break through the corresponding Gate of Order (GO). Using bugged passages between the central treasure and a specific zone is prohibited until the GO between these zones is broken."

From the above, it follows that we are not allowed to move through the sand until the GO is broken, and it doesn't matter what we plan to do. But... there are a couple more rules that, I believe, the judges and Dark himself followed when performing this action.
- a) From the general rules for transitions between zones:
"2.6.2. If the guard of the passage between zones is moved deeper into the adjacent zone, then it is allowed to enter this zone to eliminate it. If there are several guards of the passage, it is allowed to enter the adjacent zone to eliminate any guard chosen by the player. Eliminating the guard in these cases must be the first action in the new zone."
- b) from the additional rules for transitions between zones on Jebus Cross:
"- Transition between zones using the Angel Wings artifact and the Fly and Teleport spells is allowed:
...c) in cases of several GOs of one passage - to approach the GO chosen by the player, while the first action in the new zone must be to eliminate this GO."

But... these rules imply that the number of GOs on a specific passage is more than 1. In our case, as I understand it, the monarchs are the only GO of this passage. Accordingly, these rules cannot be applied in this situation, and we return to the standard rules, which, as I recall, do not allow us to enter the sand until the GO is broken. From this it follows that Dark did violate the rules by flying over the sand and attacking the monarchs, and the judges were wrong in their interpretation.