There is a problem, though. It has a guardian, a 60 foot long Green Dragon with a nasty temper! There is a way to safely pass the Guardian and claim the additional treasure, though.
Once a player claims the original treasure (if there's any left by the time you reach the purple ring), they may approach the Guardian by asking "May I please pass, sir?" (you've got to be extremely polite with cranky dragons, you know - always say please, and end your sentences with "sir").
The Guardian will ask a total of 2 questions, the answers to which are both readily available here on CB somewhere. If you get 1 right and one wrong, the Guardian will allow you to try again, either after the other team takes another turn, or one of their players addresses the Guardian and fails. If you get both wrong, the Guardian will eat your head. You certainly can't claim any treasure without a head, and are thus out of the game.
The first player to answer both questions correctly wins the extra 3 million! And since Mr. Lewis is too chicken to risk his head, the Ninja Pirate Monkeys won't be stealing any of it in the meantime.
Ya'll have to finish out Day 4 before you can access the secret crypt, though.
Just in case you want to review, here are review the original rules.