It's actually quite impressive, working a vocal based off a middle eastern scale into a Linkin Park album. Brad is heavily into middle eastern music so I imagine it was his influence, but regardless, it's actually one of the most vocally impressive thing Chester has done, and fits very nicely with the tribal feel of the song. Why is it there? Why is the keyboard in In The End? Why is the solo in The Little Things Give You Away? Same reason, It sounds awesome and fits the song.
Exactly right. Personaly i think its the best damn part of the song. its just so insane and impressive. I also love all the glitchy effects around it too, just before the end, the stop-start break for a barely a second, and everything suddenly comes back in with such force! Wow!