Until that moment, the Harmonizer would keep falling apart and fixing itself in a cycle that would end the moment the enchanted metal was too worn down to regenerate again.
The Hydras focused on identifying with Life Vision how the self-destruction spell interacted with the others and with the mana crystals. Only once they discovered from where the energy flow built up and the runes from which it was exhausted could they weave the Forgemastering circle, Disarm.
It was a spell that combined the effects of Cypher and Rewrite. Disarm's runes sequence was flexible and needed to be tailored according to the volatile nature of the spells it had to neutralize and supersede.
It took them time, effort, and several tries since at the slightest mistake the energy overload would get worse and they would have to start from scratch.