One day you are mysteriously imparted with the knowledge you are a living portal key to Sigil the City of Doors! You can use any door on earth to create a portal to a door in Sigil, the reverse also holds. The first time you appear in a random safe place in Sigil and return to our world from the door you entered through. From then on you can choose to enter or exit from any door on either side you already traveled with. The more doors you use on either side the more options you have. The portals last as long as you are touching the door or travelling though them.
What do you do?