In the various Zombicide games, my understanding is that if zombies can take two or more valid paths, they split. E.g. if there are 8 walkers in one square, and they can go one of 2 ways, you get 8 walkers go one way and another 8, previously non-existent walkers go the other way(!)
So:
- What is the justification in terms of the background story for the splitting rule?
- What is the justification from a game playing point of view? I.e. how is it better than randomly determining which way they go?