Networking with guest speaker at uni

Hi All,

In a few weeks a head of the valuation & research department of a big bank (want to keep it somewhat anonymous here ;) ) will be giving a guest lecture at a course I'm taking at my university. Given that there are at least 250 other students in the room wanting to work for him, what would be the best way to network with this man?

I've read a posting on the WSO meet up in january I believe, where the guest speaker got swamped and then was having lunch somewhat alone. I don't anticipate this happening here.