If you mute Voice during the part where you get the CD for stage controls and you wait over the vent it will break and you won't be able to progress through that. Also if voice is muted while you turn on the generators to repair the head in the west arcade it will take your head and then make you do the sequence to turn on the arcade but then won't repair the head and even if you grab another head from the raceway it will break and not let you flip the switches in the sequence to turn on the west arcade.