Why meatgrinders are terrible for creating backstory

[KorvinStarmast]

By the end, there were only about 40 soldiers from the regiment who survived. Then the Inquisition picked them up, executed half of them for being infected by genestealers, and recruited the rest as inquisition goons.

DM hands them the Dark Heresy core book and tells them to pick their characters from the 20 survivors, and throughout the campaign new characters had to be pulled from those 20.

I think that's awesome.