Expelliarmus and backfiring

[Carol]

No: HPFGUIDX 184657

DA Jones wrote:
> I'll make a slight adjustment to the theory, in order to clarify my 
> thoughts. The master can't be physically (magically) harmed in 
> combat 'against his or her wishes' by another 'wand'. <snip>

Carol responds:

I don't think that we have any evidence to support your view. All we
have is the belief that the master of the Elder Wand can't be defeated
in combat if he's using the wand, a view disproved by the defeat of
Grindelwald. (As you state, the master of the wand can certainly be
killed by other methods, such as stabbing or poison. He can also be
robbed of the wand and Stunned [Gregorovitch] or Disarmed
[Dumbledore]. In Harry's case, the Elder Wand apparently doesn't yet
recognize him as its master when it hits him with an AK, killing the
soul bit and sending him to "King's Cross." Later, when it realizes
that he's its master, it refuses to kill him: the AK strikes the
Expelliarmus and rebounds on Voldemort. But if Harry had been using
the Elder Wand, even if it had recognized him as its master, and had
used Expelliarmus while Voldemort used the AK, both spells would have
worked as usual (no Priori Incantem effect because the brother wands
aren't involved). Voldemort would have been disarmed and Harry would
have been killed. (Unless, of course, the blood protection was still
in effect, protecting from being killed by Voldemort but no one else.)

The closest we see to what you're talking about is Harry's wand going
off on its own to protect him from Voldemort, but that occurs because
Harry's holly wand recognizes the master of its brother, the yew wand,
 even though he's using an inferior wand (Lucius Malfoy's "poor
stick") and because during the Priori Incantatem, it absorbed some of
Voldemort's Dark magic, enabling it to use a spell that Harry doesn't
even know. (Which, BTW, pretty much proves that wands are sentient.)

I agree with one of your snipped points, which is that DD had no
intention of having Snape murdered by Voldemort--he needed him to
deliver that message to Harry and expected him to do so *after* LV
knew that the Horcruxes were in danger (signalled by his protection of
Nagini). The rest, however, seems to be rather fanciful speculation
with little or no canon support.

Carol, who has already given her very different views on Dumbledore's
intentions in robbing the Elder Wand of its power and sees no need to
repeat them