I queued into a random group. It was me, some new player and 2 pros. We were going through the dungeon like usual. We defeated a boss just before the final one I believe. Then me and the newer player continued forward. I was killing the mobs and noticed it was taking longer than usual. I noticed that I was alone with the newer player. I was like "well, maybe they are cleaning their inventory or something" So I continued to kill the mobs. Then the scroll to make the final boss stronger was read. That's when I was like wth? I opened up the map and saw the two pros at the final boss.
I sat there and wondered
1. Did I lag?
No, because the newer player stayed with me. The mobs are still alive.
2. They did something.
So they start fighting the boss and I am like "crap I need to get there!!" So I start running fast and all 100 mobs all behind me following. While they are fighting keep running to that cave on the side. The mobs dump on the two pros and they wipe. The newer player wipes as he tries to follow me. I am sitting in the side cave crouched near the final boss and I say
"WTF just happened?" The two pros quit instantly. The newer player then quits. I am like uhhh wth....