Lost and Found in the Void (Modern Hiccstrid)

Hiccup got in a car crash with another car, he stayed unconscious almost the whole week, his soul stayed in the Void, all empty nobody was there, until another soul appeared, a girl. They spend each other's time in the Void, until things start feeling different around each other. Both lost in the Void, but found each other on the same place at the same time. What will happen if one of them left the Void and one of them stays there forever?