Probably a good idea. Sometimes he just needs to be calmed the hell down.

Ahhh if the manga is anything to go back breaking = death or at least that's the hint. Cracking just means oops way more demonic and out of control the worse it is.

But then again there may be ways for the techs to keep him alive with the blade broken until it can be repaired, too. Especially since there's only one Kurikara.