It is always interesting to see what a show will do with a returning character; I thought they did a fairly nice job with this episode. (Though I did feel that the math problems could have been a little more complex.)
There is something particularly compelling about Richard Dean Anderson when he confronts Zito in the bell tower--I saw him make some nice choices as an actor. I felt he played the scene a little differently than a typical MacGyver scene--it made the scene very interesting, meaningful, and believable.
I was also intrigued by some discoveries I made while watching this episode.
First of all, the staircase in the bell tower looks very similar to the one in the fourth-season episode Blood Brothers. Might it be the same one?
Second, listen closely to the voice of Doctor Skinner (Lynne Moody). It is the same voice they have been using for voice-overs (such as unseen TV announcers and automated alert systems in buildings) on MacGyver since the season two opener The Human Factor. I finally had a face (and actor name) to put with that voice!