Phases through a wall

There was another skill I wanted to test. When I’d lived on Earth, the ground that I walked upon and walls that enclosed me had been solid. What would happen now? Would it be the same here?

I willed myself back into the form of an orb and floated towards the city wall; then passed right through it. The stone was very thick, and for moments I could see nothing, but then I found myself in a long straight corridor. I drifted to the end and entered a large chamber.

Starblade Book 3 Chapter 14