I remember that moment from the show, but I don't remember when Mike's tech goes onstage to fix something and Mike introduces him, so when I watched the video the first time, it was a surprise to me.
I do remember John P. playing the "Mother" solo in "Surrounded", with the screen showing the The Wall artwork. I'm not too fond of that song (or album for that matter), but it was nice seeing the band pay a subtle homage to one of their influences.