Labyrinth 2: The Wrath Of The Fire King

Puzzles Are So Annoying!!!

*Jareth's POV*

I was walking through the Labyrinth, Sara looking at everything and trying to wrap her head around my situation. "So if you aren't there she can't choose another element other than Fire?" She asked, myself giving her a look of annoyance. Why did she ask such silly questions that she has the answers to. "Once again, yes, if I am not there by the full moon, my daughter has to choose fire. Which is bad because Flare will have to teach her and turn her against me." I said, which then Sara had another puzzling look. "Who is this 'Flare'?" She asked... Finally she actually asks a question that she doesn't know the answer to! "Flare is my evil twin brother, he is the Fire King. I have the Water element of my father but still carry the Life element in me. Roselea has a choice, she can choose either water and Life..."
"and fire" Someone said to finish my already completed sentence.
"Well, if it isn't you brother, and who is this fine lady with you going through the Labyrinth the old fashioned way?" The voice said, which I knew it was my brother Flare.
"Brother, why are you in my Labyrinth?" I asked, ignoring his question. "Well, it is your daughter's 1600th birthday, the day she chooses her real powers. If I keep you away, she will be mine. I will finally have the Labyrinth, and you can't stop me." Flare said and disappears. Really?! He thinks he can't be stopped?! Wow... he need to learn more about history, bad guys don't win.

I then got to the two doors, the ones with the knockers. Sara was looking at the doors, probably trying to figure out which door to go through. "Which door leads to my castle... tell me now." I said to the knockers. "Who is this?" The left knocker said, he looked at me. "Your majesty, what a pleasure to meet you here. But we honestly don't know which door it is. Our memories were erased, but we only know this riddle..." The knocker kept blabbing, I was starting to get really irritated. "The riddle is???" I said, very annoyed at this puzzle, I was annoyed at the whole Labyrinth being turned this way. "The door that leads to the castle knows the answer to the other riddle." The knocker said, then I started getting even more annoyed. "Whats the other riddle?!" I said, yelling at the sorry excuses for door knockers. "The riddle is what occurs in every minute, twice in every moment, and never in a thousand years?" The knocker said, then I thought for a bit. Roselea and I would do riddles to each other sometimes, and I became very good at those. So I need to figure this one out.

After awhile I realized the simple answer, but the only one that one would know would be the one that could hear, the right one. "Whats the answer?" I asked the one with the knocker in his mouth, which he then mumbled something. My patience was wearing thin. I then just went through the door with the knocker and I fell.