@Kingdo In a way, it seems hypocritical for the mother to lecture her son for violence towards women, after all the stuff she had done. In another way, it shows what a monster Lawrence is. Then again, everything we have been told about this society though, is that people are just murder happy and willing to kill anyone on a whim.
Was it ever explained why Lawrence didn't just kill Tia? Just out of spite?
Also, if Lawrence had his own mother killed, the writing was on the wall for Tia.
It's almost hard to blame her mother for doing what she did, or Tia for going along with it. The story just keeps showing, that people who are not willing to kill any potential enemies, are likely to get killed themselves.