I think the Admiral have that other kind of night training in mind for Umikaze.
And probably Kawakaze is in the same night training you are thinking about
Yamakaze's on a night expedition!?
No way!
Her curfew is 9pm, see!If you have to force her to go then, Umikaze will go as well...
Wait, I'm doing night training!?
You've got Kawakaze for that, don't you?!