What made Mel Gibson snap?

Waking up to the fact that he had been used by Oksana, set up by Oksana, and that she has made a career out of having children by celebrity males (actors in particular) and then popping them for child support. In California, if you are granted child support at all, that enables you to keep petitioning courts for increases (ask Timothy Dalton; he was the other fall guy). She's under investigation by the LAPD for extortion, so she may have reached the end of this particular career path.