Sieghard is at +20 from advantage. Maybe it's be smarter to just try to finish things, but I'm going to try Strike to Stun. Sieghard will roll normal attacks until he deals damage (to maintain full Advantage) and then make a stun attempts until one connects (but doesn't have to stun) after that. If all three of Sieghard's attacks land, but Dragos isn't stunned, the third roll will be a normal attack for damage. Note that Sieghard has Street Fighting, so whichever roll is the stun attempt will be at a further +10 to hit.
As before, if Dragos is incapacitated non-lethally, Sieghard doesn't finish him off. I'd rather take him alive.
(1d100)[99] vs 76 (51 WS +5 Best Sword +20 Advantage)
(1d10+6)[12] Damage
(1d100)[91] vs 76
(1d10+6)[13] Damage
(1d100)[91] vs 76
(1d10+6)[11] Damage
... How do I manage to whiff all three of those?