Peter Brook (The Empty Space, p. 136) wrote:"When a performance is over, what remains? Fun can be forgotten, but powerful emotion also disappears and good arguments lose their thread. When emotion and argument are harnessed to a wish from the audience to see more clearly into itself then something in the mind burns. The event scorches onto the memory an outline, a taste, a trace, a smell a picture. It is the plays central image that remains, its silhouette, and if the elements are rightly blended this silhouette will be its meaning, this shape will be the essence of what it has to say. When years later I think of a striking theatrical experience I find a kernel engraved on my memory: two tramps dancing under a tree, an old woman dragging a cart, a sergeant dancing, three people on a sofa in hell[...]"
Jamy arranged his set to conclude with an extraordinarily memorable image. I expect that for most of the viewing audience, if they remember anything at all from this performance in days to come, they won't remember any very minor fiddling during card from cardbox.
All most viewers will remember is that closeup image of Craig Ferguson's card frozen in that block of ice.