>>718038308
I prefer the original CG. Also to answer your question, Arc was severely weakened due to the fact she had to use a shit ton of her energy to regenerate after Shiki cut her to pieces. Combined with the other vampires taking pot shots at her resulted in her having no energy left to stop Shiki from raping her.
But if you make Shiki rape Arc, it just results in a bad ending, so the point is moot.