If another player has a Zombie and a Pair of Zombies and I have the Shotgun and I kill his Zombie, does his Pair of Zombies move?

A: No. The reason the Pair of Zombies decides to “run away” is that, as a pair, they’ve put together enough of what’s left of their dead brains to realize that they’re in a dangerous area and need to leave. This doesn’t happen if a zombie near them simply keels over because of a distant shotgun shot.