Hey RJ, I think you made a little goof here: the episode title is "Bananas, Crackers, and Nuts," not "Bananas, Crackers, and Egg."
That being said, when I first started watching M*A*S*H as a teenager, this episode really, really confused me, and I think this actually says a lot about the Hawkeye character, and Alan Alda's skills and abilities as an actor, because it didn't really don on me at first that Hawkeye was just putting on a front for everybody - it especially didn't help that, I believe, syndication cut this exchange from reruns:
TRAPPER: Were you just acting?
HAWKEYE: You ain't seen nothin' yet!
Having the dog hooked up to oxygen is also cut, as well as Frank and Margaret discussing the possibility that Hawkeye is faking, and that calling in Captain Sherman to exam him was Margaret's idea to see if he's pulling a fast one, so it kind of makes it seem as though Hawkeye really is
losing his marbles. On top of that, Hawkeye pretending to be in love with Frank isn't exactly out of character for him either, mainly because in other episodes, we see him playfully trying to move in on Frank - if only just to get him riled up. I can imagine, with this being the early 70s, how risque it must have seemed for TV audiences (and probably the network as well) for Hawkeye to pull a stunt like that.
But again, looking back on this episode as an adult, I understand Hawkeye was just putting on an act - and he did such a good job at that.