I've never been to prison but in my opinion I would say serving a lifetime in prison would be far worse than just getting put to death.
When you're in prison for life and locked up in a prison or prison cell you're essentially dead anyway.
Imagine that torture of knowing that you'll be dying in prison and never be able to be free from those prison walls again.
I'm a person who likes to be free and not trapped somewhere and when I'm trapped inside a building or my home during bad weather such as an ice storm or snow storm etc I can barely stand it and can't wait until the weather gets good enough to go outside again.
I can understand why some prisoners who're serving a life sentence "especially at a young age" would commit suicide and get it over with.
Now when you're on death row you live in worse conditions than a normal prisoner so that could be worse as well but actually getting put to the death would be a blessing instead of having to live out decades in a prison cell with no human contact and nothing to do.