Extras are "killed" by falling pieces of a set during the explosion scene, then appear to either get back up or adjust themselves so that they won't be trampled by other extras.
When Glaucus brings Jone back to her home, the inside of her house is shown with an open air atrium represented by a painted backdrop. We can tell it is a backdrop because the sun in hitting it in such a way that the shadow of other part of the set fall across it.