When Sandstrom is struck by a car at the beginning of the episode, his shoe flies off but in the next shot he is lying on the ground and both his shoes are on.
When Sandstrom is explaining to his daughter how a virus affects people, he says that it makes thousands of copies of itself inside a single cell to the point where it bursts the cell, making thousands of holes in your cell walls. The cells of humans, like all animals, do not have cell walls. Animal cells are encased by a cell membrane (biologically completely different from a cell wall).