I'm not sure if this is intended gameplay or a bug.
-Cast magic wood
-Opponent traps a tree in a crystal wall
-Use Aelfscyne (the 5 trees into elves talisman) to turn the tree into an elf
The elf is then free, even though it still shares the same tile as the wall. You can move out, shoot out, stay in and attack an adjacent segment, etc. I'm not sure if the elf can be attacked while in the wall, I moved the elf out same turn. It did give me the option to melee the next wall over without needing to move out but I didn't do it.