These slabs represent the western continuation of drain 5401. Here, where associated floor survive (5467; 5522) the concave slabs of the drain are incorporated more or less flush with the slabs of the floor, and seem to have served to chaannel water westward. Extrapolating from this situation, perhaps in the eastern part of this area of the terrace, drain 5401 worked in conjunction with similar ashlar slabs floor, which have been robbed; however, the bedrock is higher there (necessitating construction cuts for the drain slabs), and it does not appear that a slab floor could have been laid flush with the drain, as here. Perhaps, there the drain was slightly sunken, below the floor level by a few centimeters. It is possible, though, that there was a limit originally to the floors 54567 and 5522 to the east, and that the space there was functionally and architecturally different.