"You see, when I first met her, I thought she really was Erica, come back to life..."
You give Maria a puzzled look.
"So I worry that she might be hard for you to deal with, if she reminds you of Erica too much."
You say you know that Erica is dead, you saw her in her coffin, and it has been many years now.
"I know," Maria says, "but you're also in the middle of this experiment, and I worry about what it's doing to your mental state..."
Whatever! You say you'll be fine, you can take care of yourself. You start to walk away.