Talking to himself, of course. He's moved a few tables away from Sofia, so as not to disturb her. She's not in a mood to be disturbed right now.
So,why is he hiding it from Kimberly? There are two theories: one is that he's writing the things he'd like to be able to tell her but can't. The other is that he's very shy and doesn't like to be watched while his writing.
"It's just a love letter" - Mind you, if Kimberly expected it to be the beginning of a rather complicated plan on Brisbane's part, that'd just show that she's been paying attention.
I remember writing this and thinking "What do I know enough about from high school to drop a reference to?"
Because if Brisbane got up to move, she'd follow him.
Nina pt 5 drawn by Rina Tay