She gives a gentle push and knocks the first tile, producing a literal version of the domino effect, her eyes full of childlike wonder.
The scene serves as a fitting metaphor for its titular character and the show in general. Every action of Jimmy McGill (Bob Odenkirk), every decision he made during the show, good or bad, is going to come spiralling down.
He was just too much of a coward to give it back to the world before his cancer diagnosis. But Jimmy was genuinely kind and clever (if a little wayward) who felt dwarfed by the titanic shadow cast by his brother.