Labyrinthine Sentence

The voice, deep, profound, mysterious, and resonant voice echoed though the dark, dusky, pitch black tunnel continuously repeating the numbers five two six one three five nine over and over again to a group of three siblings, a brother and two sisters, with a locked briefcase; however, the three family members could not figure out the meaning of the numbers for the life of them, but then, they realized that the voice was giving them the code for the lock on the briefcase that contained several documents to help trace them back to their family after living in an orphanage for eight years of their life with a torturous orphanage director, who treated the orphans like slaves.