On top of the roof of the vault to get in there you will have to use the combination which is 8630.
Go to the vault and click on the coins and Rookie will pop up and will talk to you.
On the ceiling of the vault because of a giant magnet caused by Herbert!!
it is 3568
Mission 3? You can see it on youtube.
I dont think there is a vault in club penguin so I dont reely know!
See the related link.
It is different every time you go on the Missing Coins mission in Club Penguin.
Just Go To This Website For A Full Guide On "How To Complete The Case Of The Missing Coins - Mission 3" The following is NOT a link http://www.club-penguin.org/club-penguin-mission/club-penguin-mission-3-case-of-the-missing-coins.html
i luv club penguin to get money, be a detective but u have to b 30 days old and go in the vault and try to complete mission 3
its club penguin rules
In G's droor