It's amazing what a proper set of clothes can do for feeling confident, and Balthier almost feels normal as he heads on in. Mr. Dorian was supposed to be there, from what he was told, and the agenda was basically a meal and conversation with a few folks.
When Balthier was still thinking of fleeing, versus actually putting the plans in motion, the last few meetings he had were either awkward talks over dinner while his father complained about nearly everything in existence, or meetings in his father's office. Which usually involved recursive letters, since you could end up with Officer Bunansa (the elder) sending Officer Bunansa (the middle one) to fetch Officer Bunansa (the one going now by Balthier) so he could speak with Doctor Bunansa (the head of the house) and so on. A pub, with live music, and the potential of people he's coming to trust is definitely better.