I agree with lcfcsunil. adsmylie had it pretty much right. One thing that's wrong in his version is after the creepy voice says "and now the flood gates will open" Rou (the lead singer) clearly does not say "wide!" He is really just saying "Yahhh!" in an inhale scream. Putting a Y in front of certain vowels enunciates words, syllables, and words like "yah". So essentially Rou's using "yah" for a dramatic effect and possibly to symbolize the water released by the flood gates. Even so, I think it makes that part of the song epic.
I agree with lcfcsunil. adsmylie had it pretty much right. One thing that's wrong in his version is after the creepy voice says "and now the flood gates will open" Rou (the lead singer) clearly does not say "wide!" He is really just saying "Yahhh!" in an inhale scream. Putting a Y in front of certain vowels enunciates words, syllables, and words like "yah". So essentially Rou's using "yah" for a dramatic effect and possibly to symbolize the water released by the flood gates. Even so, I think it makes that part of the song epic.