If a wall is sharing a border with a square of blocking terrain, and i give a figure an action to destroy, how does that work?

If i destroy the blocking terrain does the wall break too?
If i destroy the wall does the blocking terrain break where the debris markers go?

Or do they require two separate destroy actions?

Now this, I found.

Comprehensive Rules, 16.9c Destroying Walls:
When a wall adjacent to blocking terrain is destroyed, that square of blocking terrain isn’t destroyed and no debris marker is placed on it.

-J

This matters especially on the old Prison map.

Would this mean that if you break the piece of blocking that you also have to break the wall too separately?

That is correct.