No, they aren't. They both escaped. They are shown in the last chapter living somewhere next to the sea (which one, the mangaka doesn't say), and sword got a haircut. Apparently, there has a been a deal made with the infiltrated FBI agent. Helping them escape was sword's condition to help him get the warden caught red-handed. Absolutely fantastic manga with good ending. Sen and Sword are just my favorite couple ever.
Are they dead Or.Not ?