[It isn't until she has no choice, that she is finally herded into a safe zone as well. Instead, it's been spent trying to make sure that others seek and find shelter, too. While Yuuki is immortal and can't die, she knows very well that the majority of the people here can.
For that reason she wants to do all she can to prevent that. She herself is getting ready to put up an air bubble, if needed, and the dome cracks. She's remaining incredibly busy, but now it's just to distract herself from the fact that she's been separated from Zero, and she doesn't know if he's safe or not.]