N. Igma's students don't treat him with any respect at all. Igma never shows his face. Even when eating or drinking. It's only natural that Nina and Lockbolt are curious about what he looks like.
If you don't know what Lockbolt is talking about when he says he was enslaved by Igma then you need to read my 'Cortex Complex' comic. 'Nina's Academy Adventures' takes place directly after it. ^_^
More Adventures at the Academy of Evil:
Nina Cortex (c) Sierra/Radical
N. Igma and Lockbolt (c) Me