Seriously, who ends a book on a dude staring at some eggs? Answer: Someone who wants us to read the next book—Leviathan is only the first book in a trilogy, after all.
Alek gets one more chapter than Deryn, and in his final moment in the book, Dr. Barlow locks him in the machine room, where he's on egg duty making sure the remaining eggs stay warm and unbroken. He stares at the eggs, wondering what's so important about them and what kind of impact the unknown creatures inside could possibly have on the war (us too, Alek, us too).
We think it's significant that it's Alek and not Deryn who's standing there talking to eggs. This scene shows us that Alek has come a long way from fearing and hating Darwinists—he's doing a Darwinist job by keeping an eye on these eggs, and he doesn't seem too upset about it. Also, by realizing the eggs could impact the war, he takes a teeny-tiny step toward realizing that he's not the only person in the world who's responsible for it. What a concept.