GREEDO
That's the idea I've been looking
forward to killing you for a long
time.
HAN
Yes, I'll bet you have.
Suddenly the slimy alien disappears in a blinding flash of light. Han pulls his smoking gun from beneath the table as the other patrons look on in bemused amazement. Han gets up and starts out of the cantina, flipping the bartender some coins as he leaves.
HAN
Sorry about the mess.
Hmm, i missed the part where it says "Greedo fires first and then Han fires back." Guess he forgot to write it in there. And edit it in the film. And then accidentally staged it all like a classic western salloon shoot-up. And also staged the Kenobi lightsaber scene in the exact same way.