yes, there are always a distinct patterns that occurs that culminates into such violence.
I'll have to find the passage in the book, (I think) Barbarossa, but there was a stage of the battle between the Russians & Germans, fighting in Poland, where both armies were having a soft truce, each washing their clothes on either side of a River in Poland.
Whereas, 2 different Polish "resistances" were killing each other, and the big boys left them to fight it out while they did their laundry.
Once the ball of violence gets rolling it gets out of hand pretty quickly.