The fellow had been in the country for years. If he hadn't crossed the border he would now have his PhD, and would be doing what he had been doing before. No

The fellow had been in the country for years. If he hadn't crossed the border he would now have his PhD, and would be doing what he had been doing before. No one is safer because they turned him away at the border. It's either a false positive (that's most likely, considering how few terrorists there actually are), or a subtle hint to discourage his associates from ... doing things.