2nd level, blinds 50/100, eff. stacks are ~16k. I sit in the big blind with 88. Everybody folds to the BTN, a young, indian-looking guy, who was quite active, but not fishy or splashy. I've seen him minbetting a multway turn before (after flop got checked through) and then almost potting the river (HU) with pure air. I've been very calm and played few hands in the first level, so nobody has any other impression of me than being tight.

Preflop
Hero is BB with 8h 8c
BTN raises 275, Hero calls

Flop
As Ks 5c

Pot: 600
Hero checks, BTN checks

Turn
8h

Pot: 600
Hero bets 420, BTN calls

River
5s (completes possible flush draw)

Pot 1,440
Hero checks, BTN bets 850, Hero raises to 2k, BTN (thinks 3 secs) and raises to 5.7k

What do you think?