PBS Debate Moderator caught on a hot mic muttering "Oh god" as Bernie Sanders mentions Vietnam

Note to PBS: Mute your moderators' microphones. When Sen. Bernie Sanders, I-Vt., launched into an aside about the Vietnam War during the Democratic debate Thursday, a moderator could be heard muttering "Oh, God," into her microphone. PBS NewsHour anchors Gwen Ifill and Judy Woodruff asked the candidates about race relations, income inequality and Wall Street reform. But there were also a lot of unintended contributions from background noises that included people coughing, drinking water and whispering, as none of the microphones used that evening were ever muted by the debate production team.