My first play through with one character, I let them live.

My second play through with another character, I decided they all had to die (but I let Mobius live. Someone has to mind Big Mt while I'm away.)
I discovered that if you don't talk to them when you go in (after the scripting warns you that you'll be confronting Dr. Klein now) they will still be friendly towards you and willow allow you to drop C-4 and pulse mines near them. Then when you confront Dr. Klein, they go hostile, but you can detonate the C-4 - which also sets off the pulse mines - and then finish them off with the sonic emitter. It was pretty sweet doing that. Teach them not to put their cybernetic mits on my brain, heart, and spine!

I just convinced them that I was Dr. Mobius and they were quite cooperative after that.

I let them live, mainly cause I couldn't stand to kill my lover, Dala.

I loved 8, Dala, and Borous too much to kill them off...I should have let Mobius live :sadvaultboy:

This...I let them all live, but mainly THIS ^^^ :celebration:

This. Minus the Mobius part. I liked them all except Klien.