What was going through Jack's mind when Sam left him alone?
Even though Sam had left the room, Sam’s expectations still surrounded Jack.
He stared at the pencil. It was so small, so light...He had thrown two fully-grown men across a room. Why couldn't he lift this little thing off the table?
He had needed to be away from the angry yelling in the motel room--and he had been in the alley. So if he needed the pencil to be in the air...
It didn't move.
Jack remembered the pressure in his head when the not-Donatello had yelled "Do it for God!" It had been scary...and exciting...and he had felt a rush that he was strong enough to rescue his grandfather's soldiers from Hell.
Except it wasn't God's soldiers he would have let out, it was something evil.
The pencil was so insignificant. He could pick it up in his hand and hurl it across the room. It was nothing compared to a Hell gate.
What if his powers only work for evil--what if he is, like Dean says, evil simply because his father was Lucifer? What if his mother was wrong, he couldn't choose who he wanted to be, the fact he existed was abominable. After all, she'd been wrong about him having an angel watching over him--his angel was dead.
Jack's being born had killed her.
Tears in his eyes, Jack grabbed the pencil blindly and threw himself into the dark corner.