Ricin dissolved in liquid and ingested probably won't kill you if you get medical attention. Walt actually put Lydia in a tough spot...she can either stay home and chance dying, or she can go to a hospital and say "I have ricin poisoning", which is going to raise a lot of questions. The police...
Right now I'm having the same feeling I had when the credits started rolling on Attack of the Clones, which is "that was decent, but HOLY SHIT it's mostly over and they have so much to cram into the brief remaining time!"