When someone in a movie says to someone else, YJDGIDY?, it's always either the beginning of an argument or the end of a relationship. Maybe that's why Jesus doesn't say it in chapter 6 of John's Gospel. He is interested in neither.
What he is interested in, with every person and group he encounters in the Gospel of John, is initiating a dialogue that can lead to a faith that is the beginning of a relationship. He doesn't want to start an argument or end a relationship. He just wants us to get it.
(For more detail about the screenwriters conference see my blog "Knack for Noticing" http://www.patheos.com/blogs/knackfornoticing/2012/07/screenwriters-heaven/)