If a level 6 instant kills on a roll of 3-6 would a level 4 instant kill on a roll of 3-4?
But then why does a level 3 kill on a roll of 2-3? Would it not be just a 3?
I'm assuming a level 2 player would kill on a roll of 1-2?
Ah, okay, I see where your confusion is coming from. Duels are treated differently than normal combat, so instead of rolling the standard 3d6 you roll Renown + Weapon Damage. An instant kill triggers when the total is less than or equal to your level.