1. The group will always jump off the waterfall
2. The final boss will always be hard mode
If you want to swim to the the crab boss and kill it first, great. If you want to swim to the last boss and kill the mudcrabs on the bridge, even better. But please do not attack the final boss until the scroll is read. And if the boss gets aggro'd, just run to the other side of the bridge until it resets.
Doing this, you can cycle your characters through a vet hard mode dungeon in about 5 minutes for each and stock up on keys and transmutes. I thought this was common knowledge, but still see players either questing or not doing hard mode on pledge day while the group moves on or hollers "SCROLL!!" in group chat. Am I wrong? Would love to know.