Fighting in the dream world was different from fighting in the real world.
For Seiji's entire group, everyone was much stronger in the dream world compared to the real world. The specifics of how much stronger each person was differed from person to person, and neither was the power increase stable, as everything was rather hazy.
Even so, Mai's barrage of long-range sniper shots had exceeded her normal power level when she destroyed Yakushi's clone! Being able to reach this level wasn't due to her own power. It was also thanks to Seiji's support and the White Sakura Goddess's support.
At this moment, the maid felt like she was more powerful than ever before. Even if she acted as bait, she was fully confident that she would be able to protect herself.
Perhaps her confidence was actually arrogance, but she felt that it wouldn't matter. If the worst happened, she was sure that Seiji would step in to protect her.