How the heck do you open room 1-C? It's the only thing I haven't done in the game, and it makes me feel like there's another ending I have yet to find.
Idea for consideration, and light spoilers for anyone not related to the convo:
It feels a little off that after you talk with Tray after activating the final timer that nothing happens. Maybe instead make it not a live timer, and maybe Tray gives a clue on an action to perform to get another key for 1-C, which has some more story and gives Emilia
the idea to take the thing out of the tank, go to the pier (which otherwise feels kinda empty even with the purifier), and dump it into the ocean, which results in a final true best ending.