Rhinoceros Beetle 05 could not avoid the cracks from forming, but it seemed able to control where they formed and how quickly they spread with its own actions.
The beetle called up a few tactical patterns and came to a conclusion.
(Cutting off crack advancement towards body surface. Readjusting direction of collapse towards inner portions of body.)
Even if it was made of Dark Matter, no one would normally decide to allow their inner structure be eaten away to protect their outer appearance.

Toaru Majutsu no Index New Testament vol.6 ch.6 pt.10