Any recommendations for what to do with this gazillion mission branch?

I just got here and I remember it was semi-complicated.

I used to know years ago, but I have to admit replaying the game I just couldn't figure it out. I gave up and returned to the previous level.

This walkthrough at gamefaqs might help. http://www.gamefaqs.com/pc/39787-sin/faqs/15778

Thanks! I read the walkthrough, I just want to know what fellow players would think. I'm considering not pulling the switch just to see what happens, but the cause and effect in that area is so all over the place that I can't remember what I've done before.