The normally unreachable side of the wall (due to a OOC blockadge) can get people stuck if they are unlucky. I suggest either a transit on the wall, or a ladder be added to get up there and a ladder top for back down, as so that such a situation doesn't happen again and need DM help to fix. Given the other half of the wall is accesible, I think it'd be best for the other to be so as well.
Or a transition on the wall to the other side of it. As in, put a thin transition line from one side of the interior pathway and on the other. So you can use the door that exists to get on the wall, and can use the wall transition to be able to move around where you'd logically be able to walk.