I'm assuming your spy will be going up against Russians. If not, you can adjust this scenario accordingly.
The first contact works for the mentor but pretends to be a Russian agent. Not overtly—the candidate must deduce this for himself during the meeting. The contact may subtly mispronounce a word or get a fact wrong, raising the candidate's suspicions. He can then ask a leading question to confirm those suspicions without alerting the contact. That's stage 1.
Once he realizes he's meeting with a Russian spy, the candidate must deduce that the mentor's organization has been compromised. That's stage 2.
The next step for an agent, of course, would be to follow the contact once he leaves the meeting. That's stage 3.
Ostensibly the meeting is to size up the candidate in person and give him the address of a particular office. If he fails any of the three stages, he will go to that address, which of course is bogus. To get there, he must turn east upon leaving the meeting place. The contact will go west. If the candidate passes the first three stages, he will go west as well.
The fourth and final stage is in how well the candidate follows the contact. A few blocks away, the contact walks past the mentor and gives a signal. One signal means the candidate is bad at shadowing, upon which the contact shakes him. Another means he's good at shadowing, upon which the mentor reveals himself. At no point can the candidate learn anything about the mentor or his organization (the contact has false ID).
Under World. It rocks!