Regardless of whether you pass or fail the evaluation, the main stairs up remain unavailable, and you will have to find another way to get to the summoning level (ie keep exploring). Check out the rooms to the south east and west of the main evaluation area...
A key in the west rooms opens a cupboard in the east rooms, allowing you to enter another locked location on that level. A key on the table in the first eastern room opens the room at the south east corner of the level, containing the exit (head south out of the evaluation room, then east).
