I hear things that are out of place from time to time. Particularly when I first appear in the tower, I'll hear a voice that I can't quite make out. I thought maybe it's just one of the NPC sound files getting garbled when loading into the tower. I hear things on Venus now and again too. I wouldn't be surprised if Bungie threw some weird stuff in the game. We are a bunch of zombies, fighting an intangible enemy, under the direction of a tiny floating machine, linked to a giant floating machine.