Upon hearing Cui Siter's words, Lu Ban felt surprised, yet he also had a sense of "as expected."
For the creator of this world, or rather The Dark One, desired Lu Ban to forever sink into despair here. Surely, the tragic accidents befalling those around him were the last things Lu Ban wanted to see. If it were just one person, it could be considered a regret.
But if everyone were to die, then Lu Ban's existence in this world would lose all meaning. With nothing but despair and sorrow here, there would be absolutely no reason for Lu Ban to stay. Obviously, that's not the kind of scenario The Dark One had in mind when he placed Lu Ban in this place.
Hence, just as Cui Siter had said, only when everyone around Lu Ban was dead, might he then have the chance to trace back through the past and find an opportunity to leave.
However, in an ordinary day-to-day life, neither Cui Siter nor Shia would die accidentally; thus, Lu Ban couldn't simply reach the being behind the scenes.