I can understand Yukari, facing death is not what normal high school girls are trained to do (even with tankery, it's basically a sport in the GuP world, with utmost care being taken so that participants ain't injured, "Tankery is not war", after all), and even trained and seasoned soldiers have problems with that. Probably (pure and utter speculation on my part, disregard it, if you wanna) the really "military" training as opposed to the sport tankery comes after school and is only for adults.
Edit: By Hana's remark, I added the 'yuri' tag (Hana basically professed her romantic love to another girl, I think, that counts).
That stray dog is to be exterminated.Onee-chan, you're always like thaaat.So that's what it is! Onee-chan assumed too fast!This is friend-to-friend chocolate!Nishizumi rule #56, target center mass and pull the trigger.Mine is serious.Don't get so full of yourself, you dog--!Please calm down, onee-san!It's friend chocolate!Hana, shut up.Akiyama-san, I'll cover you, so run as fast as you can and don't look back.● Valentine & Panzer - 2*Piiisssss*