This is a flashback of Zalmmuna's past, hidden deep within her mind, trying not to remember but will always remember. She grows depressed day by day just thinking of this event. Here, we have her mother in a water chamber, hoping that this was the only way to keep her alive and well, Sombra keeps her in there until she either dies or heals. Poor Selena, looking at her two year old daughter for the last time, dies right in front of her... She hides this memory as a thought and never tells anypony, but now... She reveals her deep and dark past...