"Gotcha moments" refers to situations in which someone is caught or tricked, usually in a surprising or revealing way. It is often used to describe instances where someone is exposed for a mistake, contradiction, or hypocrisy. Full definition
The series seems to always eschew Hollywood - style courtroom theatrics and gotcha moments for resolutions that seem truer because they involve mistakes, bad timing, compromises, dubious ethics and sweated - out smarts. (metacritic.com)
Professor Bickmore's latest piece is somewhat less lurid, but includes a triumphalist gotcha moment in which he claims I removed a column of mine because I couldn't withstand his devastating takedown of it: (steynonline.com)