Can someone explain this ending to me?

OK! Normally I understand, or at least get the gist of, the ending of a movie. All the little untied ends etc. I mean hell I figured out Burn After Reading besides Brad Pitt's issue (Settled on hes an idiot). But THIS movie... this one is the one that escapes me. Someone explain to me the ending please. I will reward you with an imaginary cookie.

Tick Tock Goes the Clock...