It appeared to me that it was the other way around and the young kid debunked Gage. Did you notice at the end when Gage knew he was about to be shown how wrong he is in implicating the NYFD and the fires when discussing WTC 7 and then he didn't give the kid a chance to respond for he had to head off to California?
What a sneaky bafoon that Gage guy is. I wouldn't trust him to tie my shoe.