Situation; Ventilation shaft is lined with my characters, no way the enemy can get through unless they have flight or Force Leap. My opponent uses wall climber and goes right out of the shaft, over my characters. He says because the spaces are adjacent to walls, he can ignore my characters. Is that legal? Thanks in advance..................

Definition of Wall Climber:
This character ignores difficult terrain, enemy characters, low objects, and pits when moving as long as a square it occupies and a square it is moving into are adjacent to a wall

As you can see, it does say that you ignore enemy characters as long as they move along a wall. So yes, your opponent would be able to move over you as long as there is a wall.