"Lennon9@earthlink" says on this :-
"Well here is one possibility....In all of the ends of the previous verses Paul plays the high E in various manners....one note slides...sixteen note flourishes etc... When 1:43 rolls around I think John looks over at Paul and says "Leave it.." just before Paul would have hit the high E.."

Seems like coincidence - there's a definite leading "S" to the words, and sounds more like " San ee eh".

* NEW * rubbersoul_12@hotmail.com also offers :-
"John calls, "Good evening" to someone entering the studio."

* NEW * Drew Hill adds :-
John says "it's in E flat" referring to the key

* NEW * Another alternative is "It's an infinite", referring to the love that lasts for ever, and has no past