The way it happens is this:
One minute Marshall is just zooming along with lots of gas and no major complaints, drifting in blissful
fast-forward, feeling not unlike the last time he was lying in a hot tub and somebody sucked his cock.(When exactly was that? 1968? 1979?)
Totally at peace with the world. Imagine.
At this remove, it is hard to find his innocence anything but appalling.