Bran Death Instinct Order

[Rogue]

If I understand correctly, re-reading the last sentence of the description of the Quick Strike special ability, Bran Carnoth triggering his Death Instinct order can Knock down his opponent but will nonetheless get the retaliation?

answer: that's correct changes of state are applied as normal, at the end of combat so the opponent gets a chance to fight back regardless of Quick Strike (unless he dies from Bran's hand during this combat).