Here, we witness the "Luthor" in Lex. Threatened by Dr. Langston over the truth behind Lana’s pregnancy, Lex resorts to cold-blooded murder in the church crypt, proving he will do anything to keep his "prize."
The episode ends on a haunting visual: Clark standing alone in the rain, watching the limousine carry Lana away. It effectively signaled the end of the "Smallville" of old. The era of pining in the hayloft was over, replaced by a much darker, more mature conflict between the future Man of Steel and the greatest villain of his life. [S5E3] Promise
She tells Clark, "I'll be there, I promise," referring to their meeting at the barn—a promise she is forced to break. Here, we witness the "Luthor" in Lex