This is how Thunderwing imprisons the Princesses goes in Ryan's Kingdom.
[Thunderwing arrives at the Canterlot castle to steal the Alicorn magic from Princess Celestia, Princess Luna, Princess Cadance, and Princess Twilight Sparkle. Thunderwing tears the doors off their hinges and tosses them aside and approaches the Princesses and grabs Princess Celestia and tries to drain her of her Alicorn magic]
Thunderwing: What have you done?
[Princess Celestia shrugs. Thunderwing then grabs Princess Luna and tries to drain her of her Alicorn magic, but comes with the same result, then tries Princess Cadance, again same result, and finally Princess Twilight Sparkle, same result]
Thunderwing: WHERE IS YOUR MAGIC?!
Princess Celestia: Gone.
Princess Luna: Thrown away.
Princess Cadance: We lost it.
Twilight Sparkle: We gave it to someone else.
Thunderwing: Getting rid of your magic so that I cannot take it from you? That was your plan? How does it feel, knowing that soon, every Pegasus, Unicorn, and Earth Pony will bow to Unicron's will, and that there is nothing you can do to stop it?
Princess Celestia: You will not prevail, Thunderwing.
Thunderwing: Or will I?
[Thunderwing then creates four cages out of Dark Energon and imprisons the Princesses in them]
Thunderwing: With you four as my prisoners, I can now... [sees stain glass window with Ryan on it] Is this meant to be humorous?!
Thunderwing: There's a Prime-prince? Where is his castle?!