*I didn't hear or see any evidence of the engines surging. Since one could hear the noise of the engines and see the tailpipes in the video.
I did hear the pressure change in the microphone when the plane hit and it sounded immediately clipped to me.
CVRs in cockpit do pickup 'evidence" of explosions both as clipped pressure changes and ringing of the plane structure. In fact the differences in timing between the two can be used to extropolate the location of the explosion, providing the CVR power remains. (I don't see this as germain in this event ?)
Im interested in resolving any possibilities of a cargo shift at VR since this might result in enough time for a crew radio call before a loss of control.
I believe that the CVR info will not be released without significant editing, since cargo flights tend to have extra people in the cockpit. Extras who have no flight control functions tend to verbalize excitedly in cases like this