No soda, no problem. Clara was used to different types of orders and different preferences. It was why she kept herself open to whatever possibility may come her way with a request. But water was always a safe bet and if something else was wanted, it would be said and she would make it happen. But if it wasn't? No harm no foul.
"Nice to meet you, John. I'm Clara."
Introductions tended to be a good thing, especially when one was going to be spending some time hiding out from Stormtroopers.