1. The code for the L-shaped room's door (T06) is in N05, the clue is the struck-through line in the document. The map above indicates which room the clue is for.
2. In T06, there is a key and a document. The key is for T04 and the document contains clues for the emergency exit at N01, indicated by the sticky note.
3. When unlocking T04 with the key from N01, there is a map with specific rooms marked in green, exploring those areas and solving the individual puzzles will grant you the final keypad code for the emergency exit in N01
I hope this helps! Thanks for being so patient with the game, it's very heartening to know that you like it so much to not give up on it after so long. :))
We're looking forward to you finishing the game and discovering the secret rooms