This thread continues to fascinate. The C Mk 1s with a "suicide switch?" Did I miss something, for I've no recollection of volunteering for self-immolation nor of hearing of anyone else being asked to do so. To what might that term refer, pray?
It allowed the Eng to pump out all available fuel to the receivers. If the crew did that, they weren't going home. As BEagle has mentioned, it would have been extremely doubtful that it would have been considered by the crew, but it was still installed during the tanker conversions.