I think, overthewing, he was assuming that the CVR had been disabled at the same time as the transponder etc, and so had indeed recorded Act 1 of the drama.
However, the CVR can be erased (by anybody on the flight deck) by the mere push of a button.
Whereas the FDR...........
I think the CVR can only be erased with the aircraft on the ground (WOW) and the engines shutdown?