The language here of "working on a room" is a little bit unnerving, but he's right. If you want to meet new people and have interesting conversations, I've had similar experiences like this which I've enjoyed.

Furthermore, interrupting a conversation at an event like the one he describes with the question, "so what are we talking about?" after you've gotten their attention is a good way to find something to talk about, too, which isn't just the standard, "so what do you do?"