Bruce's Brightshadow Bypass

As you cast the spell, you channel magic into the mirror. This mirror becomes a portal to Brightshadow, another world that connects all mirrors, and remains open until the end of your next turn. Any creature that enters the portal is transported to a corresponding mirror that floats midair that can serve as a portal back to the Material Plane. Travel in this other world can correspond to travel in the material plane, though not necessarily in ways one would expect. Vast distances can be covered in the Material Plane by traveling relatively short distances in Brightshadow. While travel requires physical movement, the laws of physics as Material Plane-dwellers understand them don't always apply; one might not be able to simply walk up walls, but if there were a path that led up the wall, it might be possible. Brightshadow's capability as a "shortcut realm" might have to do with these strange physical anomalies. To exit Brightshadow, simply find another mirror floating in midair that leads to the material plane. While it requires a full-length mirror to enter, you can use a much smaller mirror as an exit, though the DM may determine some mirrors are simply too small.