"Behold, the angel of the Lord appeared to Joseph in a dream and said, 'Arise, take the child and his mother with you, and flee to Egypt. And stay there until I tell you. For Herod will seek out the child to destroy him.' So he got up, took the child and his mother with him by night, and fled to Egypt." (Mt 2, 13-15)
See how the Virgin Mary suffered, when Joseph told her they had to take the Child immediately and flee to Egypt, as the angel had just revealed to him in a dream, so that King Herod would not kill Him.
Look at Mary, searching for what to take and what to leave. Without hesitation she takes the Child Jesus and leaves everything behind, in order to flee with Joseph.
As it was winter, they had to endure cold, rain and wind, over steep, muddy paths. Mary, then aged fifteen, was a delicate virgin, unaccustomed to such hardships. The Holy Family didn't have any servants. They suffered greatly during their flight. While the Child shivered in the night, the parents were overcome with fatigue, crushed by hunger and fleeing, and preoccupied with the journey to an unknown country, where they knew of no one who could welcome them.
All they could think about in their flight was saving the Child Jesus. What anguish they felt when they saw their Child, the Child of God, whom they loved so much, being hunted down by such cruel enemies. Whose victim was this newborn child? Whose victim is he now?
The pain of the Mother of Sorrows is the pain of the death of innocents, the pain of injustice, the pain of being an unwilling player in this injustice since the trigger for the tyrant's fury was the birth of Jesus; the pain of being powerless and having to flee to protect Jesus.