Wall 5507 was built into the foundations of later cement wall 5350 and seemingly also 5351. It appears to continue under floor 5320 and an un-excavated layer to the north along wall 5350. The alignment is slightly off N-S (more NW-SE) and appears to belong to an earlier phase though it is unclear what else it is associated with (it was exposed during the removal of backfill from the Soprintendenza's excavation of 5354). It may be related to various fragments of similar rubble walls that reuse building materials in Room 8, or could still represent more of a foundation for 5350.