[Update: PBS says the moderator was responding to a producer, not making an editorial comment. Their statement is appended below.] Following an otherwise lackluster (if not borderline uncomfortable) attempt at discussing foreign policy, Bernie Sanders moved to something he actually could speak confidently about: Hillary Clinton’s bizarre Kissinger boast. But as Sanders opened with a Vietnam reference, one of the debate’s moderators—apparently unaware her mic was still on—could be heard sighing in the background, “Oh, god.”