Towards the end when Archer cries out loudly "Noooooo !!!" in the forest, birds are seen flying from the trees. It was in the dead of winter; all birds would have flown south so none would be nesting in the trees.
It is a common misconception that all birds fly south for the winter. In fact, about a quarter of birds do not; these include northern cardinals, blue jays, chickadees, black birds, sparrows, nuthatches, and woodpeckers.
Uranium is only mildly radioactive which means it does not make any sense as a material for a "dirty bomb" if you take that expression to mean a radiological weapon where radioactive material is scattered by a conventional high explosive. But if you take "dirty bomb" to mean an actual nuclear weapon that is designed to create an inordinate amount of lethal fallout, it makes no sense for ISIS to stress the "dirty" part. Their main worry would be the theft of the weapons grad material and the threat of terrorists using it to create a nuclear explosive, never mind what kind specifically.