[Action]
[He's not really paying attention to his surroundings as much as he's on the look-out for trouble - because that is where Luffy will be. That wave catches his attention though and he halts mid-stride, raising his own hand in a friendly although hesitant greeting.
A post office? That's as good a place as any to ask around if someone's seen the others and so he changes his course. ]
Ah-! Excuse me, Miss!
[Is it a Miss? He's not sure. The lady-dar is leaning towards a tentative "yes" and it's always better to assume it's a lady and be wrong than the other way around. ]