fifteen minutes before twelve
When it grew thin he knew they had left the frequently used tunnels and entered deserted ones . They could only retrace their steps and start again in a different direction . More maddening than the walking was the way time was running out . Inexorably the glowing hands crept around the face of Brion 's watch until they stood at fifteen minutes before twelve . `` There is a light ahead , '' Ulv whispered , and Brion almost gasped with relief . They moved slowly and silently until they stood , concealed by the darkness , looking out into a domed chamber brightly lit by glowing tubes . `` What is it ? ''