Aligned on an E-W axis across the central courtyard with threshold 5347, the entrance to Room 4. Furthers the general impression of symmetry across a N-S axis that runs through the middle of this courtyard, although this soon breaks down because this threshold leads (together with 5582) into a single, long room, rather than the pair of smaller rooms on the eastern side of the courtyard.
This appears to be a well-made theshold; in alignment with, but smaller than threshold 5582. Wall 5584 as well as floor 5585 partially covers it.
Room 18 with floor, thresholds, and eastern wall