From the response i have received so far, it seems that most of the people have a problem figuring out the lock combination in the game.

The combination is actually in the form of BINARY in one of the notes.

8421 is how you read the binary code

EXAMPLE:

0101- This is actually 5 (wherever its one, add the corresponding number. If its 0, don’t add the corresponding number)

8 -> 0
4 -> 1 = 0+4+0+1 = 5
2 -> 0
1 -> 1

I hope this helped XD