"Wait!! You have not signed those papers yet? Why? Why are you doing this? Even if we are wife and husband, We will never be happy. You will never be happy, I will not stop seeing him nor do I allow you to touch me. So why not just end this here once and for all?"
Sandra went ballistic when she heard he did not sign their divorce papers yet, Which means she is still legally his wife.
Normally she did not have a problem with it as it is just a piece of paper but now that Alex is in view she starts to think differently, She is afraid that he will misunderstand her because of this worthless relationship of hers with Dick.
So she said the things she knew he would react to the extreme as she came to learn his mood swings in the one year she had to spend in his house to survive.
She wanted to destroy this relationship no matter what, She can't take any risk of ruining things going in with Alex.