Questions about the Sin in an UW speed run!!!

Hi, I want to be able to do the Sin part in an UW speed run and I've tried a couple of times. Unfortunately I am much too slow. So here come a few questions:

1.I've found out that if I tank the darknesses in the first chamber with the wall at my right that I can safely kill them without them running away. Why doesn't this work in the 2nd chamber where the reaper is supposed to spawn? Can someone give me a screenshot of a map where I should tank in the reaper room?

2. When I solo unwanted which is the fastest way to go? And do I also have to kill the Dryders?

3. When I solo the Ice King quest, where do I tank the dryders?

myth

Didn't this just get nerfed?