When you go into Room 9, there is a strange hint, signed by 'Dr. X':
Duplicates, go forth! The hint key is keyed with a key of key! ovnr wPraor o aZcdsua fretsfdes
- Dr. X
There is a rather confusing hint:
The hint key is keyed with a key of key! Sfb lkgm ygofbq vkr trba ex sfb Dbqlkmr gm VVG. Sfks'r sfb nmjx fgms xnt'qb dbssgmd ex abygofbqgmd sfgr rsqgmd!
And, last, the keypad:
The next door will be added when this door is solved!