Why Landis killed the children (Spoilers)
I watched the film again with my mom. We both agree that Fiatlut-1 who left the other post was right, I think Ladis wanted to break the illusion about the children being safe because they lived in a nice house with parents who had money. The whole act he had with his faceless dummy was about the illusions we have in life like when he insulted that woman and then the frat brothers. He seemed to be obsessed with illusions.