After the two guards inside the corridor were lured away by two of the Yin Puppets, Bai Long made the remaining seven Yin Puppets quickly enter the dark corridor.
Not lighting a lamp despite having them in his spatial ring, Bai Long made the Yin Puppets walk in the darkness and saw as much as possible with his vision which allowed him to see a little in the dark.
Just like he had seen, the corridor wasn't too long and was only around thirty feet or so.
At the end of the corridor, Bai Long was stunned from seeing nothing other than a wall, which made it seem like he walked into a dead end.
However, remembering what the eunuch said, about seeing something like a vault before he was knocked out, Bai Long guessed that there was something hidden behind the wall.
If not, why would there be two cultivators in the Martial General stage guarding a corridor which led nowhere?
