what did mrs lovett say to turpin when sweeney killed him and when he was holding her dress? and why was she saying it?

She screamed "DIE, GOD IN HEAVEN, DIE!", because she was freaked out that he wasn't dead yet and that he was grabbing her dress.
:)Hope this helps.

then she burns in the stove :)

She Yells "die God in heaven Die" because she is down in the basement where judge turpin drops and he grabs her dress as he hasn't died yet so she screams as she doesn't expect him to still be alive!!