Why does Gatsby disappear after lunch in The Great Gatsby? What does he know that Nick and Tom don't know?

This
question is asking about a short sequence that occurs in chapter four.andare out for lunch, and
Nick sees thatis there as well. Nick tells Gatsby that he wants to say hi, and Tom jumps up
excitedly at the sight of Nick. Gatsby is not too keen on meeting Tom, and readers are told that
an unfamiliar look of embarrassment came upon Gatsby. Gatsby is normally all poise and
confidence.

When Nick tries to introduce Gatsby, Nick turns to discover that
Gatsby is no longer with them. Both readers and Nick are left confused. What Nick and Tom do not
know is that Gatsby already knows who Tom is. Gatsby knows that Tom is married to , and meeting
the husband of the woman that he is trying to win over and steal from that marriage is
definitely awkward.