I still don't know enough to have an opinion regarding X's decision.
Various possibilities:
1.) He realizes that he is a mid-round pick, but he is sick of school and just wanted out, even if it cost him a bunch of money and reduced his chances of making an NFL roster.
2.) He has a back up agreement with a CFL team and is happy to play in Saskatoon or someplace even further north after he is cut by an NFL team during try outs.
3.) Some NFL team rep has told him they want him bad enough to pick him in the 4th round. And he wanted to believe him.
4.) Some agent has told him that some NFL team will want him bad enough to pick him 4th round. And he wanted to believe him.
5.) X was on record this year in talking about how great he is. Perhaps he believes that and expects the NFL to believe it, too.
6.) X is not confident that he would have a very good season next year in the PAC and was worried that if he played next year he could drop below a mid-round selection. He certainly doesn't think he would have a good enough season to lift his draft stock 2-3 rounds, because if he believed that, the math would be overwhelmingly in favor of coming back next year.
I might be wrong and some NFL team will take him early on the second day. Assuming that is not the case, however, what else am I missing?