From her perspective having the girls tell the truth would put them in danger but staying quite would keep them out of it. Now someone else may be blamed and punished for it but at least these little ones will be safe. Such is the life of a good girl trying to make the best of things.
Matsuwa-chan!?For a shipgirl, a protector of humanity, to do something so underhanded!N-No, I really can't!!All I can do is go and set the record straight!If we don't tell anyone, then I'm sure it'll turn out fine!You just can't!!You can't!Etorofu-chan!Matsuwa doesn't care what happens to her!No... there's some truth to Matsuwa-chan's words.You think so too, right, Sensei!?So...SENSEI!?But if anything happened to you, Etorofu-chan... Matsuwa would... Matsuwa would...!!