This is your final challenge.​ You may turn the envelope marked Crossing the River Styx over now to see the image, but listen to the message below before opening the envelope. There is also a transcript of the message should you need it.
TRANSCRIPT This is your final test detective, but as you probably could have predicted, it will come in multiple parts. Just as souls had to cross the River Styx to enter the afterlife, you will have to cross my fiery river to reach freedom for the rest of your life. First, you will find a puzzle inspired by the rivers of Greek mythology. If you successfully navigate that puzzle you will gain access to the gate that allows you to cross the bridge above the fiery lake before you. At the end of the bridge, you will find a safe. Somewhere in that safe is the key to that will allow you to finally exit. You will need to solve several final puzzles to obtain said key. I look forward to watching you attempt this final challenge. No pressure, but you can still eternally perish in this trap I have set for you; your progress thus far will be meaningless if you are unable to finish the job. You may now open the envelope labeled Crossing the River Styx.