As they waded through the sump cellars, bearing east-northeast to bring up opposite the St. Pat's vaults, they suddenly discovered that the pitch dark was illuminated by a fiery flickering up ahead. Dagenham shouted and flung himself forward. The explosion that had opened the subcellars of St. Pat's had split the septum between its vaults and those of the R.C.A. buildings. Through a jagged rent in stone and earth they could peer into the bottom of the inferno.