I’ve played through the game at least 3 times now on three different difficulties - easy, normal, and legendary. If I understand, the bandana door will not open unless you’ve refrained from damaging Sentinels in the last mission.
I’ve done this.
Multiple times.
The door stays closed. I’ve played through on easy and ran through every single room without killing unless it was absolutely necessary, and the door is still closed. I’ve also done this on Normal difficulty, and the door stays closed. Are sentinels hurting themselves or something?
Just to clarify, are you mistaking the door?
There is another door which looks similar to it with cloaked Elites inside, but that one never opens, because it is in fact the backwall of the room you are looking to enter.
Continue further into the mission and there should be another door which is actually open.
In silent auditorium it should be that you go through mission not damaging any sentinels and then at the end of the mission the door should be open in place just before riding the final elevator.
Don’t think it’s bugged as I got it easily enough, but if it isn’t opening when gone through mission then could do a ticket and get 343 to look into it
If you fall off the edge of the map and a sentinel follows you and explodes because it went too low, I’m pretty sure it counts as damaging it/killing it and the door won’t open.