There is a story in Hinduism about a king who was approached and given one wish by God. Desiring to be immortal, the king told God that he wished he would never be killed indoors or outdoors. As He promised, God granted him his wish. The king, therefore, lived his life as he wished without any fears of being killed. However, one day, as he was standing in the doorway, with one foot indoors and the other outdoors, God appeared in the form of a lion and killed the king. As the king was neither indoors nor outdoors, God had found a way to kill the king without going against His word. He had found the kings most vulnerable spot. Therefore, this led to the superstition that it is bad luck to stand in the middle of a doorway.
Preeya first heard this story and learned of the superstition when she was a child from her mother. She was lingering around the doorway waiting for her mom to come out when her mother saw this and pulled Preeya away from the doorway. She informed her of the story and told her that it was extremely bad luck to stand in the middle of the doorway. By standing in a position where even the king was most vulnerable, she was exposing herself to all the evil of the world. It was almost like inviting bad luck to enter into her life. Therefore, even now, Preeya does not stand in the middle of the doorway for fear of bad luck.
The superstition also seems to be based off the idea that the doorway serves as a portal between the living and the spiritual world. Because an individual standing in the middle is neither in the living nor the netherworld, he is neither alive nor dead. As this denies the person entrance into either world, this is a most unlucky position to be in. Standing in the middle of the doorway therefore represents the spirit of a lost soul stuck between the two worlds. Thus, it is unlucky to stand even for a moment in the middle of the doorway.