blood bending is common knowledge now because of aang and the groups adventures. They stated that aang told the stroies to every one jinora "read" about them so its in writing even the story of Zukor mom is known to almost every one ( except us :|) don't see why he would skip over the blood bending part escapillay for the fire nation people that it got used on and some fire nation people knew about it since it was used on them. hama is part of their stroy in the fire nation so they told people about it ( probably unknowing that someone would be able to use it without being taught) and if not maybe korra will ask about blood bending when she wakes up.
also creme cailburn buggiesbunny whatever if there was someone to balence out the avatara who would balence out this avatar 2.0? it would continue forever because there'd need to be an avatar 3.0 for 2.0 and a 4.0 for 3.0 you get my point no?
also there IS a new episode next week check your guides or check the wiki
and at bold its like she is pissed at him for that and tahts the whole reason why this is happening right now xd
You're not understanding it correctly. They balance each other out, the second one doesn't just balance the first one out. In the case the 2nd one would do something, the first Avatar would have the power to stop him too. That's what it means to have balance, what you're talking about is not balance. Water can put out fire, but fire can evaporate water too.
Unless you're not going to say then what if both of them failed, but then you're not within the Avatar context anymore, then you might as well start questioning why wood is for instance not an element and such kind of stuff.
How did he know there was a metal box? Tracking him to the hideout doesn't equate that, she could be in a metal cage or god knows how many other ways you can bind and trap someone.
You don't know if he could see the cage or not, it was downstairs, Tarrlok was standing in the doorway...
Unless he peered downstairs off-camera then it doesn't add up, he picks up Tarrlok right after he energybends him anyway.
The potentially strongest bender in the world of which you know she has at least mastered 3 elements is not someone you can just lock away in a normal cell or place. On top of that based on what we have seen in Republic City metal cells are quite common as, unless you're a metal bender, you can lock away any kind of bender in it. And there is really no difference between a metal box or cage, at least not one that's important. Also he knew Tarrlok had Korra. So if you count all of that together with the fact that Amon stood in the doorway, as he went behind Tarrlok, that if he didn't know it yet before he would have realized it on that moment that Korra was in a metal cage. If you see a large metal cage (and if you watch the episode you'll see it's perfectly possible to see the cage from the doorway, especially when there's a light right above the cage) in the middle of a room of which you know that there's a 3-element bender, well then the connection is easily made. Also Korra and Tarrlok were speaking with each other, so it's almost certain Amon heard them speaking as it has been clearly shown that Korra could hear them speaking.
Seriously you're nitpicking on something extremely minor with no importance whatsoever to the story insinuating it might be some important clue for the plot. This can't even be considered a flaw of the makers as it's perfectly possible that Amon knew of Korra being in a metal cage. Also when he took Tarrlok's bending away, the screen changed to his men. In the next screen he was seeing with Tarrlok on his shoulder, so he could have easily looked down the stairs. We can't know whether he did that or not, however it's completely possible he did and that makes your entire statement void. If it's completely possible that he knows she's in a metal box, then the statement that it might be some kind of important clue looses its entire foundation as it's based on the reasoning that it's illogical for him to know that.