I don't know, the fight totally went out of Vincent when Phil said his father had done a runner. Surely he would have protested if he didn't believe it? I took the promise to kill Phil as long-standing hatred exacerbated by Pearl's kidnap - and also probably because he can't stand the humiliation of being "owned" by a petty thug like Phil.
It also may be that he believed it at the time, but has now got his fight back and dismissed it as lies.
However, I might be completely wrong; I frequently am.
Phil will never completely get his comeuppance unless Steve decides to leave EE for good. Bully boy Phil Mitchell is too good value as a soap character we love to hate to keep down for long. Like him or loathe him, Phil nearly always manages to keep us glued to the screen. Plus, Steve can make Phil vulnerable and even compassionate when needed, so he's not a one dimensional panto villain. Although I dislike the character of Phil, I love watching him (and occasionally even find myself rooting for him despite myself).
Saying that, he is supposed to have suffered horribly at the hands of Gavin, which is why he's such a mess now. I see his his reckless taunting of Vincent as that of a man who feels he has nothing left to lose - which means he's broken inside.
Sharon certainly saw him for the thug he is tonight, but sadly she's become his doormat. I'd love to see Sharon permanently gain the upper hand in their relationship!