Ezra Levant, master of ceremonies for the event, said that it would be physically dangerous for Coulter to continue with the event, and so the whole thing was canceled.
The student at Western Ontario was asking a questions specifically regarding Coulter's claim that Muslims should take "flying carpets" instead of airplanes. This student said that she did not have a flying carpet, and asked what other mode of transportation Coulter would recommend. That's when Coulter made the camel comment
Earlier, Coulter had justified her position on Canadian public television:
I can say it a lot quicker with a joke, and by the way, they wouldn't be bringing me in here for a speech if I never told a joke, if I never used satire.