You'd have to reach the done first, and turn back into your human form (since the birds can't attack), then prep an attack, THEN finally break through the dome, and Erde has all that time to put more whatever he uses into it in order to reinforce (that is, prep) it against an attack. From the information I was given earlier, you can add preps to an attack after it's initiated, so long as you put more energy into it (or in this case, add dirt).

And unless the perfect defense has an equal number of preps behind it and a legitimate way to avoid the damage (for instance, a perfect defense focused on dodging would do nothing at all against a giant stone dome crashing in on Ysolda), it's not going to work.

As LeeRoy pointed out before, you're on a writing forum, not at a table. I think the concept of exalted characters is pretty awesome, I was even in an RP with them on another site, but you can't just spit out a boatload of tabletop rules and expect them to apply here. The ones that make sense in the setting and situation? Absolutely. But there aren't any automatics. Everything has a chance of failure if your opponent is clever/resourceful/powerful enough.

*drops two more pennies in a jar on the floor*

Also: if this sounds rude I apologize. I just woke up to be greeted by all this... *waves his hand in the general direction of the last two pages* ...and haven't had a coffee yet.