What would a sotapanna do? There are many arguments whether a sotapanna has a perfect morality/sila or not. But let's base this topic on this Sutta:


  With what four factors of a stream enterer is he endowed?
  
  ...Is endowed with virtues that are not broken, not defective, not
  spotted, consistent, not blemished, not enslaved, praised by the wise
  as conducive to concentration and desired by the noble ones He is
  endowed with these four factors of a stream enterer....Anguttara Nikaya 9.27


Now, for example, a deadly worm is in the stomach of a sotapanna's child. The only thing to help his child is to kill the worm otherwise his child will die. With his perfect morality, what would a sotapanna do, will a sotapanna (naturally) let his child die?
My guess is that a Sotapan would look into alternative removal of the worm but eventually probably get rid of it one way or another.