Another puzzle about Voldemort's wand

[finwitch]

No: HPFGUIDX 55015

Meg gave following part of the point where "Harry's curse" would have 
been:

> 
> She and the other two shadowy figures began to pace around the 
inner walls
> of the golden web, while the Death Eaters flitted around the 
outside of
> it... and Voldemort's dead victims whispered as they circled the 
duelers,
> whispered words of encouragement to Harry, and hissed words Harry 
couldn't
> hear to Voldemort.
...
And comments that Harry's curse does not appear in the regurgitation 
of spells.

However, what do we except to see? The curse failed. It hit back to 
Voldemort, saving Harry. Are you certain that the shadowy figures 
beginning to pace around wasn't the echo of that failed spell? That 
they encourage Harry, and whisper something to Voldemort?
Sure, enduring something or killing someone has given visible echo, 
torture a scream (that was heard) - I don't see why the curse that 
failed couldn't have been the one that made the figures pace around...

Or maybe just that nothing happened?

-- Finwitch