You're right... I've decided it's not dinosaurs at all, but the large monster we never see is a manifestation of the group's collective unconscious "survivor guilt", which is of course an obvious homage to "Forbidden Planet", itself based on Shakespeare's "The Tempest", with it's allegory of the awakening of the long-suppressed parts of human spirit in the late renaissance, and the relationship of that awakening to the opening of the New World.

Just kidding.

I may be wrong, but my first reaction is that you're really stretching to find deep intrinsic significance in a screenplay that may have none at all.

But then, I didn't watch the latest episode. Perhaps I simply missed the deep significance because it happened in almost the last place one would expect.... that is, on TV.