It wasn't as if something unexpected approached Claire and put her in danger. She only entered a situation that she'd been ready to enter for a long time.
Just like everyone else in the palace, Claire, Serena, Hugo, and Persia also dispatched themselves to take care of the enemies from Straea.
While Hugo and Persia led the 16 Swords to fight against Malefice Straea's most powerful and loyal Gods, Claire and Serena confronted Malefice himself.
They were the most powerful people in the entire palace, so it was only right for them to take on the fight themselves.
Malefice was second only to Malevalon, and with Malevalon gone, he was now the highest authority of the Straea Clan. As long as he died, the rest would lose their morale and reason to fight.
It wasn't like danger instantly revealed itself to the two women.
They, Damien's mother and aunt, confidently approached the battle.