Do you mean Mr. Bester?
It was good at pretending to be other people, he just didn’t know enough to make sure that the other person was the only one that Legilimens saw when reading his mind.
I don’t remember at this point which one it was, but the GGP text suggests Quirrel was in fact the one to test him then.
As for the mechanics of it—you may be right, I mostly recall that it didn’t actually work.
Do you mean Mr. Bester?
It was good at pretending to be other people, he just didn’t know enough to make sure that the other person was the only one that Legilimens saw when reading his mind.
I don’t remember at this point which one it was, but the GGP text suggests Quirrel was in fact the one to test him then.
As for the mechanics of it—you may be right, I mostly recall that it didn’t actually work.