If you ended up in Sigil. No, I don't mean your character, or a fantasy version of you, I mean you. As in, the person sitting at the computer reading this. Imagine if you got up to go to the bathroom, walked through a one-way portal to Sigil from your bathroom door. What would you do?
Me? Well first of all, I'd probably pee my pants. Then spend a few days running in terror from Sigils various citizens. If I managed to live, I'd either try and get a job, maybe work in a shop or something. OR find the first portal to Elysium. I mean, is being entrapped in Elysium really all that bad?
Depends on your alignment.
BoGr Guide to Missile Combat:
1) Equip a bow or crossbow.
2) Roll a natural 1 on d20.
3) ?????
4) Profit!