I was flipping through my strategy guide for FFX and when I got to the Mushroom Rock section, it said I can change it so Gatta dies instead of Luzzu.
It says I have to talk to Gatta twice and pick the second option both times. I tried it (and I got the same choices both times, actually) and I couldn't do it anymore, so I figured that's what I was supposed to do.
It didn't work.
I've tried it on three separate play-throughs (yah...I've been through this one a lot) and Luzzu always dies.