It was a way to drum up interest in the media for his book.
That, and nothing more. He’s getting worldwide publicity.
He knows it’s very unlikely he’ll ever serve time over this.
A couple of days getting ‘close attention’ from the Trump Admin would just be par for the course.
Comey knows exactly what questions are usually asked at such meetings. He is unworried about it. Maybe the Trump Team can give Comey something unexpected to actually BE worried about. Anything is possible.