Picking up his pace, Harry began to follow the sound.
"Kill… kill… kill…"
As he rounded the corner, he crashed into Ron, who was coming in a different direction and was covered in dirt – he had almost certainly been scrubbing something, somewhere.
"What're you doing?" he frowned, confused as his friend carried on past him at pace, one hand stuck to the wall.
At the next bend, they came across Hermione, sitting against one of the window ledges, and the girl looked up from the text book she had been reading when she heard them, looking a little dazed.
"Harry?"
Finally, Harry stopped.
"Did you hear it?" he asked them both, hopeful.
"Hear what?" Ron asked.
"That voice."
"Voice?" Hermione frowned, standing up and picking up a small stack of other books from beside her. "What voice?"
"I heard it first in Lockhart's office. And then again just now," he began.
"It's time…"
"It's moving," Harry realised. "I think it's going to kill."
And then he took off at a run, his two friends in hot pursuit.
"Harry, hold up!" Ron called.
But Harry didn't slow down – at least not for a few corridors more, at which point he lost all track of the voice he thought he had been following.