You can check out the link here if you would like to read the riddle prior to the solution.
The key points to the rules riddle are as follows:
• If the fleeing squad takes 25% casualties in a single phase, it is required to take another panic check.
• Since it is fleeing it will automatically fail said panic check, sending it fleeing an additional 2d6”
• The second round of shooting also puts it below 50%, so it will not be able to rally- if it miraculously stays on the table (Unless an order restores it)
+2 Internets to rkik, who nailed the full explanation. This shows why one should not always ignore a fleeing troops choice. Shooting them just a little bit more as they flee, or tank shocking them, as phantom phoenix suggested, results in them fleeing further. Savvy players can use this to ensure the enemy breaks off the table or ends up closer to an enemy unit so that it cannot rally.