If that law about retreat is true, I'm sure glad I live here in Florida and not Mass. Retreat in your own home?? That is pure crap.
You can sure say that again.
You do not have to retreat if you are in your domicile (that includes a tent, by the way) or car in Missouri, either. I'm told that the law was enacted to correct some bad case law.
The original "duty to retreat" concept existed for a reason, but its extension into the occupied home exceeds all standards of reasonableness by a long shot, in my opinion.