SU 5368 is the threshold of a room. Two seemingly identical thresholds lie to the north of wall 5318. SU 5368 is associated with the earlier, monumental phase of ashlar architecture. This threshold is clearly associated with a similar red tufo ashlar wall, visible in section just to the south, on the same orientation of those to the orth (SU 5347 and 5345) When this structure had gone out of use, it was built over by the concrete wall 5367 and associated floor 5325.