Apparently, this has something to do with the fact that Zebrina's animations in the game include her drinking lots of tea, and then having a very panicked expression as if she had to go to the bathroom.
I'll use this insteadYes... I was just so nervous when I met the Knight Commander that I got very thirsty...I'm sorry, but I really need to go to the bathroom...No way! But there aren't any bathrooms nearby... Let's hurry and find one!You're right...! We got to find someplace nearby...Zebrina, what are you thinking!?Are you okay? I mean, you drank all of that water in one gulp.Near...Ah...!Nearby...Phew~!MugiWhat's wrong?ZebrinaExcuse me, could you please let me borrow that cup for a bit?