I suppose now is the time where it becomes clear whether the story can hold up when instead of one long dungeon dive, she deals with intelligent beings and is OP
@Liquidxlax: She probably figured that the door had to be extremely sturdy, since it's keeping the monsters in = regular attacks won't cut it...except that she forgot she's now stronger than at least some of the monsters in the Lower Layer, and the door's designed to withstand Upper Layer monsters...