Visible crew/equipment: When the teacher is pairing up the students, a boom mic drops down from the top of the screen and is visible for about one second. (00:01:00)
Revealing mistake: A little oversight on the part of the producers. At the final scores that we are shown, Amy has $10,000, TJ has $9,800, and Travis has $2,400. This all adds up to $22,200. Even if they only answered $400 questions (which we can see that they don't), that's about 55 questions at best, only in the first half. That would run way longer, probably about three or four times as long, as any normal game show. And there's no mention of any other rules regarding the scores so there's no reason to think that there are bonus questions that could raise it that much.
Answer: It's reckless and irresponsible and it's not something that he does normally. But, it is something that Marcus would do.