I wouldn't answer by fear that they would lock me up ^^.
But honestly I feel that for people that never gone through this there is no right answer. Whatever you'll say they will find a way to track it back to your mental illness if you have one or they'll say that you have a biased view on life bla bla. Look how all the other people on earth live on just fine etc.
My answer would be : I did not sign for this. Yes I'm probably a broken human, but I don't see why I should keep trying, there is no reward at the end. Just let me leave. Stop pushing your healthy human biased view on life on me. Accept the fact that everyone has a different perspective.
Edit : Well in your interview the last person says the same thing : What's the point if we're already dead anyway. I don't see flaws in this logic but apparently, doctors can ?
I think most people want to stop suffering, that's all. And we're the only species on this planet aware of death. Other animals can't commit suicide.
We can. Isn't it just a natural thing to push the red button if you're aware of its existence, knowing that it will end your pain ?