Scene didn't make sense
The doctor comes by for a visit and is going to talk to Lucy about bringing her back to the hospital. The daughter asks what Lucy and the doctor talked about and Lucy's response is something to the effect of, "Oh, nothing much."
It's meant to look like Lucy killed the doctor and has no ability to cover it up. In retrospect, this makes no sense. Did Lucy even talk to the doctor? Was she pretending to remember to cover up her growing insanity? Since we know Lucy didn't kill the doctor, what was going on?
Your cockfights suck, you bastard.