It was a combination of seeing the monster ready to take a swing at her once it reformed, and seeing the fireball falling from the sky, that made Maka roll away from the impact. Any brunt of fire that tries to catch onto her is absorbed by the scythe, so she's no worse for wear.

But then she realizes that Masaru was in the center of the blast and scrapes up to her feet. "Masaru! Masaru!" Oh god, is he going to be okay?