Forerunner ship durability 1

Then—the unexpected. While the enormous yet ephemeral band of the Halo slowly disappeared into the violet-black maw at the center of the portal, something brilliant white pushed through from the other side. Compared with the Halo, it was tiny, but considerable in its own right: a third fortress. Council security was calling in all available might to secure the system.

Even before it had emerged halfway, the fortress began to loose clouds of fighters—at this distance, they resembled a puff of pollen from a flower—and fire its weapons in a sequential radiance. The inner curve of the Halo, even protected by waves of hard light, could not stand up long to this assault from within its own radius.

The fortress’s commanders and ancillas must have known they were dooming themselves as well as the Halo. The installation began a spectacular disintegrative sequence. The visible half of the ring bent in opposite directions, then shattered into five great arcs. We passed near the largest of these segments, perhaps a hundred kilometers from the inner surface. Released from the rotational integrity of the full ring, the segment moved outward, given an additional outward twist by the asymmetric breakup. One end swept toward us like a great swinging blade. Minutes from contact, our craft kicked itself into a new course, and we crossed the width of the approaching arc with seconds to spare, buffeted by rising plumes of icy cloud.

- - -

The dome had suffered awful damage. The fortress was out of action and in its last throes, but the chaos of destruction was not yet done with it. A curled, tortured loop of ring at least five hundred kilometers long spun from the debris cloud and cut through the fortress like a sword through bread. This impact shoved the great vessel out of our path, and in its wake, left a narrow void through which our sensors could see the rim of the portal, still glowing, still holding its form—a miracle, I thought—and cut through the fortress like a sword through bread.
(Halo:Cryptum; Ch.38)