Black Knight:
Who dares to challenge the Black Knight?
Arthur:
I do not challenge you.
The Black Knight stares impassively and says nothing.
Arthur:
I am Arthur, King of the Britons.
Hint of a pause as he waits for a reaction which doesn’t come.
Arthur is only slightly thrown.
Arthur:
I seek the bravest and the finest knights in all the world to join me in my court at Camelot …
The Black Knight remains silent.
Arthur:
You have proved yourself worthy.… Will you join me?
Silence.
Arthur:
A man of your strength and skill would be the chief of all my knights …
Black Knight:
Never.
Arthur:
You make me sad. But so be it. Come Patsy.
As he moves, the Black Knight bars the way.
Black Knight:
None shall pass.
Arthur:
What?
Black Knight:
None shall pass.
Arthur:
I have no quarrel with you, brave Sir Knight, but I must cross this bridge.
Black Knight:
Then you shall die.
Arthur:
I command you, as King of the Britons to stand aside.
Black Knight:
I move for no man.
Arthur:
So be it!
Arthur draws his sword and approaches the Black Knight.
A furious fight now starts lasting about fifteen seconds at which point Arthur delivers a mighty blow which completely severs the Black Knight’s left arm at the shoulder.
Arthur steps back triumphantly.
Arthur:
Now stand aside worthy adversary.
Black Knight(Glancing at his shoulder):
‘Tis but a scratch.”
Arthur:
A scratch? Your arm’s off.
Black Knight:
No, it isn’t.
Arthur (Pointing to the arm on ground):
Well, what’s that then?”
Black Knight:
I’ve had worse.
Arthur:
You’re a liar.
Black Knight:
Come on you pansy!
Another ten seconds furious fighting till Arthur chops the Black Knight’s other arm off,also at the shoulder.
The arm plus sword, lies on the ground.
Arthur:
Victory is mine. (sinking to his knees)
I thank thee O Lord that in thy …”
Black Knight:
Come on then.
Arthur:
What?
He kicks Arthur hard on the side of the helmet. Arthur gets up still holding his sword.
The Black Knight comes after him kicking.
Arthur:
You are indeed brave Sir Knight, but the fight is mine.
Black Knight:
Had enough?
Arthur:
You stupid bastard. You haven’t got any arms left.
Black Knight:
Course I have.
Arthur:
Look!
Black Knight:
What! Just a flesh wound. (kicks Arthur)
Arthur:
Stop that.
Black Knight (kicking him):
Had enough … ?”
Arthur:
I’ll have your leg.
He is kicked.
Arthur:
Right!
The Black Knight kicks him again and Arthur chops his leg off.
The Black Knight keeps his balance with difficulty.
Black Knight:
I’ll do you for that.
Arthur:
You’ll what …?
Black Knight:
Come here.
Arthur:
What are you going to do – bleed on me?
Black Knight:
I’m invincible!
Arthur:
You’re a looney.
Black Knight:
The Black Knight always triumphs. Have at you!
Arthur takes his last leg off.
The Black Knight’s body lands upright.
Black Knight:
All right, we’ll call it a draw.
Arthur:
Come, Patsy.
Arthur and Patsy start to cross the bridge.
Black Knight:
Running away eh? You yellow bastard, Come back here and take what’s coming to you. I’ll bite your legs off!
thingsthatmadeanimpression 
Why do you think the Black Knight says “We’ll call it a draw”? Why not King Arthur? The Black Knight yells after them calling them cowards and enticing them to come back and fight. I would think it more likely that King Arthur called it a draw, being magnanimous as you would expect.
The Black Knight, a contestant in severe distress, is searching for any means to avoid an inglorious defeat.
He is no longer able to strike a winning blow, with King Arthur having methodically removed each of his limbs.
The Black Knight seeks some recompense for his predicament, with a draw an infinitely more desirable outcome of their altercation.
King Arthur firmly believes he has a divine right to lead the Britons, and with that feels empowered to conquer and vanquish any who stand in his way. His reputation and prowess with the sword are important to him, and it is with arrogance that he inflicts defeat, with the thought of snatching a draw from the jaws of victory, simply abhorrent to him.