What does 1 Samuel 10:21 mean?

Then he had the tribe of Benjamin come forward by its families, and the family of Matri was chosen. Finally, Saul son of Kish was picked. But when they looked for him, he was nowhere to be found. 1 Samuel 10:21 - Modern Text Bible

(The process narrows down to Saul, but when it's time to present him, Saul is missing.)