Picture this: the banished prince of the Fire Nation is in the middle of the Final Confrontation with his sister. He claims there's "something off about her. I can't explain it, but she's slipping." So, he thinks he can beat her on his own, without Katara getting hurt. They are nearly evenly matched in this fight, unlike the last few times, so there is no clear winner at first. Then, of course, Zuko starts getting cocky. "No lightning today? What's the matter, afraid I'll redirect it?" That set her off. "I can finish this once and for all," She was thinking. So, she begins charging up for her most powerful attack, while Zuko is readying himself for it. Then, without warning, Azula aims her lightning not at Zuko, but Katara. Zuko sees what is going to happen and, in desperation, jumps in front of Katara, allowing the lightning to hit him instead of her. Now, here comes the question that you've been asking since you saw the title: Why couldn't he redirect it? I have a few theories.
He was too stunned by the fact that Azula wasn't aiming for him and just didn't think about his actions until he was facedown in the dirt, his entire body crying out in agony.
He did try. You saw his position. He had the correct stance and everything. Maybe his head wasn't quite caught up with the rest of him, or maybe he was just thinking, I won't be able to make it out of this one, but I at least should protect Katara, and did what Iroh warned him never to do: directed the lightning through his chest, which caused almost instant death. Which leads up to my next theory…
He redirected it successfully, but couldn't bear to kill his sister. But, he also didn't want to hurt Katara, so at the last minute tries to absorb the lightning; halting it in its tracks. This, also, he was warned of by his uncle, who told him that he was not controlling it, merely guiding it. But, he tried to absorb it before it reached his other arm, and caused an internal explosion; which explains the scar he ended up with.
He didn't try to redirect it, he just thought his arms looked cool when he leaped into he air like that. Or he had a death wish. Or maybe he just thought Katara would like him more if he nearly died trying to save her. Or, he just wanted to look heroic and hunky, which he did magnificently.
And that pretty much sums that up. So, what did you think? Do you have any theories as to why this or that happened? I may do more of these for AtLA, so give me some suggestions. Also, I don't really want to explain my opinion on the shippings, but if you guys want to know my opinion, I might do something.
Also, you know what song matches Zuko perfectly? I sure don't. Tell me in the reviews what you think.
See ya!