In The Hero of Ages, there is a scene where
The First Generation explains to Sazed in a conversation that the atium Ruin wants is in the Homeland.
However, Ruin doesn't seem to try to get it until quite a while later, after many troops have moved there, and keeps doing what it had been far away. In other scenes, Elend was avoiding talking because it could hear conversations. Why couldn't Ruin hear this conversation?