Glad they showed thorough examples, but it boils down to:
You can always see into a Ruin.
Only units that are wholly within a Ruin can draw sight lines out.
If your unit is partially within the Ruin, it still can’t see out of the Ruin (because it’s not wholly within yet). But it can still draw its normal sight lines to visible targets as usual (because normal vision), and it can still see into that ruin (because you always can lol). It just can’t see out the far side until it’s wholly within.
Okay, so Ruins lol.
Glad they showed thorough examples, but it boils down to:
If your unit is partially within the Ruin, it still can’t see out of the Ruin (because it’s not wholly within yet). But it can still draw its normal sight lines to visible targets as usual (because normal vision), and it can still see into that ruin (because you always can lol). It just can’t see out the far side until it’s wholly within.
Did I get it right?
That is how it looks to me.