The soldiers were already on them.

For a moment it seemed as though the cohort was about to drive the whole swarm of the marauders over the sea-wall, and make them pay dear for their night's diversion.

But the masterly energy of Demetrius turned the scale.

With barely a score of men behind him, he charged the nearest century so impetuously that it broke like water before him; and when sheer numbers had swept his little group back, the other pirates had rallied on the very brink of tie sea-wall, and returned to the charge.
Never was battle waged more desperately.

The pirates knew that to be driven back meant to fall over a high embankment into water so shallow as to give little safety in a dive; capture implied crucifixion.