Nodding politely without understanding anything he's saying... You can practically see the question marks popping up around Kay's head as Estinien talks. Aerial combat, Ishgard... Dragon-slaying!?!

"Hang on, back up. There are DRAGONS where you come from!?" she exclaims in shock, and QUITE loudly to boot. You've done it now, buddy. Now she'll never leave you alone.