(Made an account just to post this :P)
Dunno if anyone else has found the key for Lux Apartments yet in Zone Zero, but there's a puzzle inside that has you looking for stuff that lights up on the ground. I checked all the spots that lit up in the room in the picture but I haven't gotten the item and this should be the final room. I'm expecting the item from this room to open the door/room to the immediate right (you can kinda see the room in the picture), There's no where else for me to go, and I'm 90% sure this puzzle has something to do with the Gible Gate later on in the area. A