It takes a considerable effort for Cecily to convince herself to move toward the fray. This is no time to be a coward, no matter how unprepared she is for this kind of fighting. When an arrow whizzes over her head she knows she has to move. At least she can do something
if they're within the reach of her sword. As she approaches the fight she keeps up her singing. It's the least she can do to aid her companions.