Why is this thread surviving on R&N? Far more relevant threads that fit the forum description have been binned or demoted in the past. Because the mods have allowed it to develop to five pages of albeit well intentioned passenger questioning and mildly interesting but totally irrelevant breathing apparatus discussion it has attracted the attention of the Idiot Press and they have quoted excitable guesswork/nonsense that has turned a routine turn-back into something it wasn't, complete with "panic on the flighdeck".
So mods, why is it still here?