Ok. I will bite.

I want a quest that starts in a main city in a prominent location. You have to make a delivery which turns you fugitive.

At this point All player characters are seamlessly phased out and now are ai hostile npcs. However when i say seamless it would actially look like all your fellow players were now hunting you down to prevent quest completion.

Alternately if they were lazy they could just make you killable for the duration of the quest and let human nature do what it does best.