I'm not very sure why, but the following sentence structure came out from my mind:
Disclaimer: this is a first draft.
The realization just came to her now. Or perhaps, she knew it all along; it just that she didn't want to accept it. She was alone in a small, compressed space, with the rest of the world very far away from her. And maybe she would never be able to come back to it. Ruth, Benjamin, and the people she loved and cared about—she would probably never seen them again. Things would change. They would change from one state to another, just like ice turns into water, and water into gas.
Is that sentence structure allowed in fiction? Is OK right to use the em dash in this situation? (Does it read clumsily?)