(TL;DR, screens are below)
Last night I was in a delve without a shortcut looped back to the beginning, like most do. So when I got to the end, I had to backtrack all the way through the delve to exit (or wayshrine, I suppose, but didn't care to spend the gold). I admit, I was in a rush so I just sprinted all the way back through, agro'ing but ignoring basically all the mobs in between. Naturally, they chased me.
Have you ever opened a door, but then ran away from it? The screen goes black, like it's about to load, but then pops back to normal since you walked away from the door. Something similar to that happened to me, but with comical consequences. I had reached the exit but likely at the same time the server registered my 'leaving' the dungeon, I also got attacked and damaged by one of the mobs chasing me. As a result, the screen faded to black but then popped back to normal and I was still in the dungeon. I turned to take care of the mobs.
For those of you unaware of archer skills, one of our skills pushes the enemy away as well as making your character jump backwards as well. I used this skill since the mob was right on my butt, and the skill ended up pushing me back through the door I had just 'opened,' but not gone through. The result? Outside of the map, and oh man did I have fun with it. I know I have heard and seen /plenty/ of cases where players fall through stairs or even just the ground and fall into the abyss - this is not unheard of in many games. But I have yet to see someone talk about something like this happening to them.
http://puu.sh/902qa
To the left, on top of that ridge, is the door which I was pushed through.
http://puu.sh/902qZ
Turning 180 degrees from the previous screenshot, I see this.
http://puu.sh/902rK
I ventured a ways, then turned around again to get another shot of the dungeon landscape.
http://puu.sh/902wE
Even further away.
http://puu.sh/902BG
The edge of the world.
http://puu.sh/902Ca
It was very amusing.
http://puu.sh/902Hx
I actually accidentally walked off the edge, and predictably I fell infinitely. Eventually the server kicked me saying I had reached the message rate cap (IE: spamming), even though through this entire ordeal I hadn't typed a word.
I eventually got out by wayshrine.