One time William Lane Craig was challenged by a mischievous audience during a Q&A session of a debate with Sam Harris(? I think). The "student" pretended he had supernatural visions and Craig immediately called his bluff and dismissed him.
In his book, he mentioned personal and abusive challenge on him by the students he had Q&A with. "I find that my reaction to these students is not anger, but rather simply feeling sorry for them..." is a good point. Though, I believe he was a bit teed off at that student with "visions". It is not easy to "speak the truth in love" (Eph. 4:15).
www.youtube.com/watch?v=vg7p1BjP2dA#t=110m0s