Sit and go tournament, blinds $1/$2. Everyone has about $100.
Several calls ($2) to to me middle position, with pocket pair 10c 10h.

I raised to $12. All folded except opponent who acts before me.

(Pot = ~$30) Flop: JavaScript 10s 4c
Opponent raised $10. I re-raised to $35. Opponent called.

(Pot = $100) Turn: 10d (Jackpot!)
Opponent raised $25. I re-raised $50 (I thought this will put him all in, but he actually have $3 left, my bad). Opponent called.

(Pot = $190) River: Qc
Opponent raised $3 (all-in).

And he turned over J J. An extremely unfortunate flop for me turned 180 degrees.

Is there something I, or my opponent could have improved? If I were him I would re-raised all in on flop already. But the 10 10 lucky bastard would have called anyways. I wonder why he did not raise pre-flop... maybe just a passive guy overall.

The opponent acted before me, so he just called ($2) when it was his turn to act. I was a little surprised of that.

Yep. You don't flop the 2nd best set to the best set very often. And to turn the quad to reverse fate it is quite a memory.