In Season 1, Mandy Milkovich is played by Jane Levy, but from season 2 on, Mandy is played by Emma Greenwell.
While Lip is talking to Professor Hearst, it is assumed that they are at The University of Chicago, as shown in Season 1. However, Lip and Hearst are actually walking through McCormick Place, which is a large convention center.
Although his name is in the opening credits, Justin Chatwin does not appear in this - or the next episode.