He told them not to touch her. He told them she didn't want to be force-fed - he can delay, that is allhe can do, and from the intensity of the current pain the Oath is not amused -

(Another fairy had crashed in nearly the same spot, he'd heard the terrified thoughts and thought he could at least manage things better, the second time, had gone out to meet him, and as he'd walked in the world had frozen around him, so he couldn't move -

"I swear to you," Thauron had said, "that I have the power to give you the remaining two Silmarils, that I have leave to do so, and that if you tell me the fairy's name I will give you both Silmarils."

"I don't want them," he'd said truthfully, not that it mattered at all.)

He could delay. He was delaying.