you have to consider that Impa already knew this was going to happen and had to let things play out the way they did.
Talking about Impa, anyone wish that the Impa/Zelda friendship was a little more fleshed out? Besides just showing us everything from Zelda's point of view in the end-credits? I mean, when Zelda said goodbye to Impa forever, and they came back from the past and the old lady had the same bracelet, I'll admit, with the emotional lofty music, some tears fell. Really. But I think if they had shown us more of their friendship before that point in the game, somehow, then I would have been straight out balling.
Oh, and I totally didn't see that twist coming. Good job Aonuma!