Should all chiefs fail, the army retreats for two turns before they can try again. Gladiator Revolutionaries are a difficult lot. They require a Spartacus and his two main chiefs to lead the Army. If Spartacus falls, a coin is flipped for each leader. All revolutionaries hold their position.
Heads means one assumed control.
If both flip heads, the Army is so charged up over the loss of their leader that they will continue to fight even if the new leaders are killed. If one flips heads, he assumed control. Should he be killed, then the process of making a new leader continues. Should both leaders fail to roll, the army must retreat two turns before the sub-chiefs attempt to try again to gain control. The gladiators alone do not need a leader, as they are trained to fight alone.