Paths and routes are seperate so anyone can die and the story will continue.
Path C and D being driven by tyson is only because thats tysons character, he doesn't back down and responds with agression to most situations because he doesn't know how els to act. Compare that to OZ who's happy to stand back a watch, Orlando who will break down into tears at most things and then there's Hoss who wants to make everyone happy and get along.
When everything goes to shit of course tyson would take control, he doesn't understand his own feelings but he knows he wants to protect dave at all cost by any means necessary and has the most dominant personality to force the issue.
I remember Grizz doing a post about how the routes work in detail but cant remember where and cant find it so i'm sure he will post next time hes in the comments.