1. [we've gone] means "we've been staying"? What does that mean exactly?
We've gone -> we have gone. The verb is "go". "go" denotes movement, right? Change? It means "we have gone from point/state/situation to another".
2. [survive to literally killing ourselves] means "prevent to suiside"?
You're grouping the words wrong. It's not "survive to literally killing ourselves". It's "from learning to survive" and "to literally killing ourselves".
"learning to survive" is point A
"literally killing ourselves" is point B
We have gone from point A (from learning to survive) to point B (literally killing ourselves).
(A점에서 B점까지) except point A and B are not places, they're situations or states.
3. I don't understand well why [to killing ourselves] was used. "killing" is a noun in the sentence?
Yes, killing is a noun, specifically a gerund. Just like "learning" in "learning to survive".
I like DRAWING. Drawing is a noun, a gerund.