Resilience requires clear command succession

War can remove both a commander and a deputy, so a formation needs prepared third and fourth successors. In the brigade example, the chief artillery officer can take over because that officer already has the communications equipment needed to coordinate operations. A senior battalion commander provides another successor, and the order of succession is settled before operations begin. Everyone must know who takes command when officers become unavailable. A film scene set at Rorke's Drift illustrates a formal fallback: officers compare the dates of their commissions to establish seniority.