starting with "The door swung open".
To add even more challenge,
you could end with "The door swung shut",
and also try to have exactly 200 words.
Here is my piece which meets all the criteria. :)
The door swung open letting in a whiff of antiseptic which she could taste at the back of her throat. She shifted on the cold metal table, her paper gown crinkling as the taller doctor cleared his throat. She looked at the floor as the red haired one put the film up on the glowing wall. The taller one spoke now in a monotonous tone, she watched his worn loafers carefully as he swayed back and forth. She didn’t need to listen to his words; she’d seen in the way he had held the clipboard like a shield against his chest as if she was contagious. It was back. She would need the toque that Nona had made her when the hair began to fall out. In the silence following the proclamation she found the courage to look at the pictures of her body stripped of skin. It surprised her to see how beautiful the cancer was, like heavenly bodies hanging in the dark night. The red haired one cleared his throat waiting for a response. She couldn’t break the silence. The picture looked benign and yet wasn’t. She could not tear herself away. Even as the door swung shut.