Power Play, Lily's Trick
Each domain had a breaking point, which was connected to the point that would ethereally appear outside in the material plane.
That ethereal point outside could be used to enter someone's domain forcefully as well, but once inside, it would be hard to find that point.
However, there was one way to cancel someone's domain forcefully and exit, but it required a powerful and highly perceptive way to use one's spiritual power.
Erix and Rin had sufficient spiritual power and even a high-quality medium of it.
Spiritual Mystic Eye!
As long as they carefully spread their senses and find the breaking point in their domain, they could attack that point with a condensed and powerful attack, creating an ethereal hole in that breaking point—an exit.