The classification levels below "top secret" involve a laughable laxity. But spying is a very real problem, and the government needs to screen people who handle actual state secrets.
I'm guessing that they are (in 4 hours) trying to simulate some of the pressures that go on when people are recruited and act as spies, and especially when they are blackmailed into spying. All the pressure tactics probably give testers a fair idea of how quickly people crack.
Huh, in that case it is better to learn to lie very well, then tell them after the successful test what you lied about. That seems like a different kind of training.
I'm guessing that they are (in 4 hours) trying to simulate some of the pressures that go on when people are recruited and act as spies, and especially when they are blackmailed into spying. All the pressure tactics probably give testers a fair idea of how quickly people crack.