Get first the "axe ending" and then the "wax ending" to get the third one. Therefore, first pick the axe and after getting that ending: replay the game > pick the wax / second object > obtain the ending > replay.
Tatsunami would say something about thinking he had a nightmare after the axe ending that's your signal = means you're doing it right. He has to repeat it after the wax / 2nd object ending,and after getting that ooneTatsunami mentions feeling this already happened,after that interact with the door. Then Haru says to check again the note / paper,you'll have to read it 4-5 times > you'll obtain a new redacted? object > interact with the door, and then it should show up!
In case you did the endings in the opposite order, gonna need to delete the unzipped / decompressed file and decompress again the compresed one, in order to be able to play again. Hope this helps! ♡