It was dusk, and Fluttershy was stressed, which was not that out of the ordinary. Twilight hadn't come to tell her what Derpy had been like. Well, Twi didn't exactly say she would...
A knock on the door startled Fluttershy out of her deep thoughts. "H-hello? Who is it?"
"Oh! It's Derpy!" Phase four.
Fluttershy was still creeped out by the gray pegasus, but she was the element of Kindness. "Come in..."
Derpy had cleaned herself up, and all the blood was gone. "Thanks. I had a lot of fun with Twilight today. She's a really nice pony."
Fluttershy nodded. "Where is she now?"
"Back at the library, I think. Can I have some tea? I'm cold." Derpy sat down.
"O-okay," When Fluttershy disappeared into the kitchen, Derpy took the rope she had hidden in her bag and hid it in her lap. She didn't normally do it like this, but she couldn't risk anything. Phase five.
When Fluttershy came out with the tea, Derpy leapt up and pinned her to the ground with the rope. "Sorry it had to be like this... No one can know."
The teacups shattered and the boiling water burned Fluttershy as she struggled and kicked, coughing. "W-what? Why?" she choked.
"You were suspicious. I can't take risks like that."
Fluttershy's struggling died down, and she gave up the fight. There was no way out.

Meanwhile, Rarity was nearing Fluttershy's cottage to get pet supplies. She was shocked when she heard coughing and screaming. "What? That's not like Fluttershy," The screams faded away, but Rarity got closer too investigate. This is what she heard.

"D-derpy! I was right... You're psychotic... She should have..."
Then the coughing stopped.
"I try, Fluttershy, I try..."

Rarity burst through the door to see Derpy standing over a dead Fluttershy with a rope in her hooves. "Why?" Rarity sobbed. "Someone needs to know!" She turned to go out of the cottage, but Derpy spotted a pair of scissors with some paper.
The gray pegasus grabbed them and tackled Rarity. "You won't be going anywhere..."
And she stabbed Rarity in the heart. Blood spattered all over the room, but Derpy didn't care. "You aren't dead yet, but in a few minutes you will be because of blood loss. Have fun."

Derpy laughed like the maniac she was as she galloped out into the night.
Phase six: Complete.