Well, he doesn’t know it’s an intelligence op at that time, right? He’s only overwhelmed and doesn’t actually know what cooperation means. They’re subverting the same instinct that people in America have which needs to be protected by “Don’t talk to the police” which is “you’ve done nothing wrong. Just be upfront and we’ll help you out”. Then as time passes, the hold constricts around him.
An allegation of rape will have finished off his career. No doubt about it. Take the Assange situation, then add an actual video of him having sex. Even if it were obviously not a single cut, enough people will hate him for it. “It’s a GRU op” people will be treated as conspiracy theorists.
I’m not saying the Assange situation is like this (that he was entrapped) to be clear, but the reactions you read online to that will be similar to what this man would have received had the video been made public.
On the up-side, he wouldn’t have been imprisoned for spying against his country. On the downside, his blossoming career would have ended. But in the moment, the upside seems unlikely, rare and far off. The downside is immediate. The upside is subject to hyperbolic discounting.
The reason I doubt the theory of “this happens quietly many times” is that KAPO would be aware of the strategy and would have every incentive to inoculate Estonians about it, and to crow about their native heroes who escaped Russian clutches. Instead they only allowed revealing of the strategy via a caught spy.