OOP: The Prophecy ball

[phoenixtears288 at cs.com]

No: HPFGUIDX 62271

After a good nights sleep, I'm up and ready to think. However, me, like others, has a question. 

Spoiler Space: 

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OK, while the Death Eaters cornered H/R/H/G/N/L where Harry and Voldemort's prophocy was, Malfoy said something that the only people that could touch the prophecy was those who it is about. 

So, later on in the story, Hermione/Ron/Luna/Nevi/Ginny made some balls of prophecy explode, and in effect being that white figures came out and said the prophecy. So my question is, why didn't the Death Eaters just make it explode while Voldemort was there. 

I'm so confused. 

"Phoenix tears"