"Hold!" hissed a new voice, as Percy was midway through lunging desperately sideways to try to avoid the green death that would have shortly been headed his way. Quirrell's voice had stopped on the instant when it was interrupted by a great echoing hiss, a voice that made shivers run up Percy's spine and made him very much want to run away as fast as he could and never, ever try to do anything this stupid ever again. (Which was sort of how he'd felt on Halloween, and also for the entire last hour or so of his life; if this was how heroing felt all the time, Percy was starting to really wonder how anything heroic ever got done, ever.) "We can use the boy!"