I just love how casually the narrative caption puts things.
Oh, she just fell off a building. It happens. Superman spends most of his days catching people who fall off buildings (OSHA and building codes are pretty lax in Metropolis) I mean you can't fight a super-villain or apocalyptic alien every day. It also seems to imply Lois took a second job as a building inspector at some point.
Oh, Silver Age, how we love you.