Using the same setup as level-1, you will require a wall at hip-height or greater connected to a second, perpendicular wall.
Stand in the corner of where the two walls meet and place one hand only on the hip-height wall.
Place your opposite foot into the corner where the two walls meet - just as you would with a step-vault. Move your hand a little further and try to extend your body a little further away from the wall, slightly more than a regular step-vault.
Now try to move the foot on the wall onto the perpendicular wall, even if you're still resting the foot on the hip-height wall.
Create a stable position using both hand and foot. Bring the back leg off the floor and pass it over the wall and landing on this same leg.
You must repeat this three times in both directions making sure you do three reps with the left hand on the hip-height wall, and then three reps with the right hand on the wall.