Because their story didn’t end at the right time, in the right place, because they let their feelings go to waste, it was written, I think, that Eugene and Tatiana would find each other ten years later, one morning in winter, under terra firma on the Meteor, Line 14 (magenta) of the Paris metro.
Eugene and Tatiana could have fallen in love. If things had gone differently. But time has found them far apart, leading separate lives.
Until they meet once more in Paris…