Yura (deliberately) misheard Yura's request for 'something carbonated' as 'some (size) AAs'. They are both pronounced /tansan/.
...I don't even know how to translate this pun.
I'm an idiot, manganese batteries have carbon in them. I'm a chemist, I should know that, but for some reason it slipped my mind.
Updated
That's not what I meant.Haah... so hot. It's so hot it makes me want to drink something carbonated.Here, the AAs.
Originally the pun is that "carbonic acid" (i.e. carbonated) and AA (batteries) are pronounced the same, as /tansan/.Hey, Yura, could you buy something carbonated for me after you back from training?I'm baaaaack! Bought and brought them.What kind?...Wrong.Anything will do. I'll leave it to you.Zinc-carbon batteries...eh? Ah, you want alkaline ones instead?