This layer appears to be the cut for the deposition of two burials. The fact that the W loculus was empty and appears to be cut less regularly than the E suggests that it was not completed, perhaps because of the less compact character of the tufo on that side (itself suggested by the numerous fragments of collapse bedrock recovered within the fill of the loculus).
Top layer of sarcophagus in Tomb 25
Cut at intersection of two cuts in Tomb 25