It can be pronounced either way - I've always pronounced it -VI- talking about the spine / neck, and -VAI- talking about womb bits, but I'm not aware of any rules about it, arbitrary or otherwise.
Than being said - he's a massive cunt. Pronounced K-U-N-ihopehisfacerotsofftheutterballbag-T.
If he can pronounce 'cervix', why can't he pronounce 'cervical'?