Is Helen being coached what to say.
 

No way on this earth would she have said no to the 15k, I think she's being fed what to say in certain situations.

No, I think she just turned down the 15k.

She turned down 15k and No i dont think she is been coached.

As much as I dislike her, I believe she sincerely turned down the money of her own accord.

As much as I detest her, loyalty is high on her list both for others towards her and vice versa.

Chris, Mark and Ash took the money because they don't believe they can win.
Helen, Winston, Pav and Christopher refused the money because they believe they can win. If they take the money, it harms their chances of winning.