She's protecting the little people in the audience.
Actually, only Mata Nui's head and left hand made it down to Aqua Magna. The rest of the pieces landed on other planets or are even floating through space. This is why Makuta was so crushed, his original ambition is utterly impossible in this timeline.
Well..... I did try to make it simple enough for a non-fan to follow. I figured if non-fans couldn't enjoy it, then I'd failed. The paradigm shift here is it's no longer just Takua's story. Usually he's the audience surrogate, us vicariously admiring the Toa through him. Now, for the first time, the TOA are right there with us, as confused about the world as we are.
I tried to think of ways to show the face, maybe something like a screen with a blueprint or cross section, but that felt kinda weird to me. And there's not much I could do to show it physically without destroying much more of the island.