Ok I'll bite.
the fact of the matter is Corax was terrified to face Curze and run ran from him.
The bottom line is Corax saw that Curze was far stronger than him when he forcefully, and effortlessly lifted Corax's straining lightning claw with one hand.
Again false. Far stronger? Please. He WAS strained, the reason he has a 'calm' face during this scene is to make it seem that he's not. It plays right into the whole 'psychological warfare/instill fear' thing he goes for.
Corax was fearful for his life which caused him to run
Again not true. He fled because he was heading to the areas of the battle which were most fierce (as stated by the enemy themselves) and to assist his men in escaping, he cared about keeping his legion alive.
in hindsight he hated himself for being weaker than Curze thus he created psychological justification for why he ran.
No, he hated himself for letting Curze's parlor tricks get under his skin and for not staying and denying the enemy two commanders.
he was unable to escape Curze's grasp.
And yet he did just that.
Curze could have killed Corax in that moment, and there would have been nothing that Corax could have done to stop it. Corax had lost his whip, Curze crushed Corax's lightning claw, and Curze could have stabbed Coraxz with his other free hand.
He could have punched Curze in the face before he had a chance OR stopped his free claw with his other free hand(since only one was directed at Lorgar).
Have a nice day sir.