I think when Sami finds out about the affair between EJ and Abby, I think she should be so shocked that she just walks out. She takes the children and goes to Lucas. Sami finds out she is dying of some type of disease and does a JR Ewing sets someone up for her "death". The set up can be for EJ, Abby, Nick or Stefano. I think Kate would help her, if Sami was protecting the kids and wanted Lucas to raise them. Kate may even support Sami to marry Lucas in order to have a stronger hold for the kids. Lucas knows she dying but is clueless about the fake "murder". Lucas will find Sami before she dies and they will profess their love to each other before she dies in his arms.