What emerged was a single oval chamber, roughly four metres long and just under a metre and a half wide, with a ceiling height of about one metre, its long axis running north-east to south-west. That low ceiling tells you something about how these spaces were used: a souterrain was never meant for standing upright. You crouched, you crawled, you kept whatever needed keeping cool and hidden.

At the north-east end of the chamber, there is a blocked creepway, a low connecting passage that would originally have led either to an entrance or to further chambers beyond. Whether additional chambers exist on the other side of that blockage remains unclear. On the western side, the remains of an infilled construction shaft are still visible, the shaft being the practical means by which the builders excavated the chamber from above before sealing the opening once the work was done. Today, access is through a collapsed section of the roof to the west, and the floor is covered with the rubble and spoil that came down with it. The collapse, frustrating as it is for the structure's integrity, is in fact how the chamber became accessible at all after the 1991 discovery.