Yes, mentioned, but worth mentioning it again! Paul's breakdown of "Tomorrow Never Knows," one of my favorite Beatles songs that is so often overlooked, was fascinating. That one song alone broke so many barriers in the studio and opened up a world of possibilities for folks like Brian Wilson to step into and explore.
I can't remember if it's been mentioned on this thread. But every music / Rock'n Roll fan needs to watch the new doc on Hulu with Rick Rubin talking to Paul McCartney. There are 6 - 1/2hr episodes. It is very well done.