You must run the encryption procedure called by
ThreadEncryptProcedure. But you want to focus on just one thread, in order to solve the problem that the FBI agents detected. Changing the code is not an option, because it will take more time than expected, and you might introduce new bugs to the encryption engine. Thus, let's freeze the threads we are not interested in!
Now, we are going to leave one encryption thread running alone to focus on its code without the other threads disturbing our debugging procedure: