It seems like a point like that could be made just as easily at a less crucial moment. Alternatively, it is a strange emphasis to place on such a pivotal event in Jewish religious history, though perhaps that would depend on one's interpretation of the 'gist' of the Law...
I am not as acquainted with the style and purport of the Old Testament as I am with the New, but I have read that it uses a similar 'parable language'. From the alchemical or esoteric point of view, "Egypt" would in fact be a significant marker, in an of itself
, indicating not a polity but a kind of inner state which people live in. This "inner state" is given form by the historical and stylized representation of Egypt itself, its general drift of life, and the exodus that took place from it (succeeded by wandering in the desert, or wilderness--compare when Christ was wandering and tempted by the devil).