One of Spencer Spencer's henchmen injects Lois with a lethal toxin, claiming he has an antidote to the toxin but is withholding it as a bargaining chip to ensure Clark does not resist them. This plot point is never resolved or even addressed again.
Just before building the hut Clark said he figured the hotel people would find them before nightfall or the boat people would come back and realize they put them in the wrong place and so they will need shelter. That doesn't make sense because if either of those happened they wouldn't need shelter, it's only if neither of those happen that they would need the hut. And all day Clark was sure they would be found so it makes no sense he wanted to build shelter.