I can remove a wall but still be able to have a ray collide with a previous "space state" of when the wall was originally there? This doesn't seem to work for storage of the map's current state and seems to just be a reference to the world's state and not it's own separate instance:
var phys_dir_space = _world.get_world().direct_space_state
if _original_direct_space_state == null:
_original_direct_space_state = phys_dir_space