to go for a vincent actually means go take a piss.
the phrase comes from a Quentin Tarantino film PULP FICTION, in which the character named Vincent Vega (starring John Travolta), is always "oh so desperate" to use the bathroom facilities all the time.
Vincent: ...so not only i shot that guy in the face, i have a very bad luck walking out of the toilets... never consider to go for a Vincent, unless you expect somethingcatastrophic to happen later...
Mark: "Hey, how's life? Doing anything this weekend?"
Marcus: " Nah. Just Clash Royale and Clash of Clans."
Mark: "Ur a potato. Your just pulling a Vincent."
Marcus: " Wow, what an honor."
Mark: " Ummm. no. Ur just a potato."
Someone who says that they would come to an event or have accepted an invitation, but pulls out at the very last minute by coming up with an excuse from their list of excuses.
Jeff: Looks like Vincent is going to be Pulling a Vincent again for the badminton.
Kevin: I totally called it half an hour ago! What excuse did he give this time?
Jeff: Apparently boss called him last minute.