A murmuration has no leader and no plan. Each starling reacts only to the handful of neighbours it can see, obeying three simple local rules: keep a little space, steer the way they steer (follow), and drift toward the middle of the group (gather).
Nothing coordinates the whole. The sweeping, shape-shifting cloud is an emergent property of those local rules — order that no single bird intends or commands.
When a hawk dives, the flock splits and folds around it, then closes like water: moving as one makes any single bird hard to single out. Predation is a (+/−) interaction — bad for the prey, good for the predator — and it is exactly the pressure that makes coordinated flocking pay off.
That is why biologists count coordinated flocking as an adaptation: a behaviour shaped by natural selection because the birds that flock survive the hawk more often than the birds that scatter.
Something in the simulation stopped unexpectedly — the lesson continues without it. You can move on; nothing you did was wrong.