And of course while you are establishing just what is going on and probably severely distracted as a high side failure will normally be rapid, appreciate the differences with the RPM warning system.
LOW RPM - light plus audio
HIGH RPM - light only - NO AUDIO
It can affect the correct response and subsequent outcome.
VH-HOQ
Neither pilot appeared to recognise that the rotor RPM warning light, with the absence of the rotor low audio signal, was suggestive of a high rotor RPM and not a low rotor RPM situation.