Perkin is a prisoner in the Tower of London after pretending to be the dead Prince Richard, the rightful heir to the throne currently occupied by King Henry VII. A beefeater, or Warden of the Tower, is responsible for torturing prisoners. Good luck Perkin.
The Facts
It's true that Beefeaters were originally those that tortured prisoners in the Tower. Although it was not permitted under English law but who is going to argue with the King? The rack was really known as the Duke of Exeter's daughter.
Perkin was born in Tournai (modern day Belgium) and did start his career in Portugal where he was encouraged to pretend to be a claimant to the throne, one of the escaped boys from the Tower, Richard. He went to Ireland were support was slow to arrive. So he went to France instead. His 'Aunt Margaret' decided to support his claim.
His men landed at Deal but Perkin didn't fight on the beach. Or anywhere else for that matter. He went to Scotland and did marry Lady Catherine Gordon. But he abandoned the Scottish as well! He did indeed hide in a cask of wine to avoid capture.
He did go on the run and fled to Beaulieu to beg for sanctuary. Although under arrest, he was given a lot of freedom and lived with his wife in one of Henry's palaces. He took his chance and fled custody but only got as far as Sheen before he was recaptured and brought to the Tower where he was more secure. Warwick was indeed in the cell above and did drill a hole through the floor to talk to Perkin. Perkin was eventually beheaded.