When Cynthia falls down the stairs, the way she was falling doesn't match the position she is shown in the next shot. It also looks like it's not the actor, but a double.
When the house collapses, Cynthia changes positions through shots, but she fell unconscious, and couldn't possibly move.
When Harris is seen burned sitting at the chair next to the window , area
around his eyes still has normal skin, possibly because it was too
uncomfortable or not possible to put makeup there.