Thea wasn't really in any position to reach out to anyone. She didn't know how long Orrin tortured her. It could have been hours; it could have been days. He didn't even bother to ask her for the formula...he just wailed on her, curse after curse, and occasionally with his fists. Then it all stopped.
Orrin wiped off his hands and approached her. "Now then," he said softly, his voice seeming more distant than it was-Thea was pretty sure she had a concussion after all of this. "Now I will have the formula." Orrin reached into her mind, and though Thea tried to put the wall back up, she had been weakened too much by the hours of torture to fight him.
"So simple," Orrin whispered. "So elegant. You will make history, my dear. Fear not, I will be sure that everyone knows your name and that you were the one responsible for bringing the Dark Lord back."
Thea groaned, all but whimpering as Nott came back down. "They should be arriving any minute. Do you have the formula?"
"I do," said Orrin and began giving instructions for Nott to set up as the others began to apparate in.
Thea struggled to think clearly through the pain, to focus on what was happening. She had to stop them, somehow, but there didn't seem to be a way to do that. She had to get her wand back, first and foremost. Without it, she could do nothing.
She knew the odds were against her, but she started looking for her wand, spotting it just a few feet from her. She glanced over at the Elite members, but they were too focused on getting set up, on getting ready to cast the spell that would reverse the dais, to notice anything Thea was doing.
Carefully, she pulled herself across the floor, having to bite her tongue to keep from screaming from the pain. She couldn't let them hear her. It took her several moments to get close enough to reach her wand. By that point, the Elite were already chanting, and it was too late for her to stop them. But maybe she could change who they brought back.
Using a non-verbal summoning spell she summoned the mortar, pestle, cauldron, and potion ingredients she needed, keeping a close eye on the chanting wizards. They were focused on the spell. Hurrying, Thea mixed the ingredients she needed, before writing a name on a bit of parchment and adding it to the potion. Then she put the mix into a vial, disillusioned it, and sent it flying towards the dais. The bottle smashed against the dais, and the dais began to smoke.
Orrin looked her way. "Keep chanting," he told them, though he was worried about what Thea had done.
After a moment, a figure stepped out of the dais, but it wasn't Voldemort: it was Fred Weasley.