Conventionally, after one party catches the Magic Fruit Talent, the most commonly used means of imprisonment is either sea stone handcuffs or sea stone cages, plus several big chains, such as Doflamenco. Sea stone is the bane of the devil's fruit ability. With the sea stone cage, Luffy can't escape as long as he is properly guarded outside. However, the practices of Aunt Pirate and Naval Headquarters are somewhat different after all, and Luffy is not restricted by sea stones.
Four Kings of One Piece, my aunt's son has a clerical officer named Mondo, who can create a book space out of thin air, make people fall into a trance state, and also create a "book cage", so that the creatures locked inside can live forever! The strange creatures collected by Luffy and his aunt over the years are kept in the book. From the animation point of view, Luffy is still a rubber body without restrictions on its ability to use.
You should also find that it is not the door that traps Luffy. Brin can easily enter without anyone's help, and Luffy said that he can leave as long as his hand is broken, which proves this. The crux of the problem lies in the white nail on Luffy and Nami's head. Since Luffy is not restricted in use, why not try to pull it out with your feet? Nami can't do this, but as a rubber nut artist, he can do it easily.
Back in those days, Karp once held Luffy upside down. At that time, Luffy's feet were obviously elongated, but Luffy didn't seem to use his feet very much. Everyone forgot that he was actually free to stretch all over! Maybe the nail can't be pulled out, but it's obviously unreasonable to break the hand directly without trying. Nami even gave up directly. With her meteorological attainments, it is easy to light up a small thing. If not, let Luffy help you and see where you can find the golden hoop. All the above are personal opinions. Don't spray if you don't like it