Why do atheist euthanasia proponents consider nothingness preferable to suffering?

I have heard some atheists support euthanasia, on the grounds that death is preferable to agony. But I don't understand this; if there is no afterlife, death isn't a relief. It's true nothingness, the deceased won't experience painlessness, they won't experience anything at all. To me, this seems like euthanasia doesn't "put them out of their misery", it just hides their misery from us. It doesn't benefit the dead at all, only the living. Euthanasia proponents seem to be stating the following: Agony < Death < Bearable life Why, if there is no afterlife, isn't the hierarchy this: Death < Agony < Bearable life I'm an atheist, and this is the conclusion I reached. I had emergency surgery several years ago. I remember laying in the operating room as they prepped me for surgery. I remember the anesthesia technician hooking up my IV to the drugs that would render me unconscious, and then the next moment (from my point of view anyways), I was in the recovery room. I had no sense that time had passed or any memory from during the surgery. It seemed like one instant I was in the OR, the next I was in the recovery room. I think that is what death is like, except there's no recovery room afterwards. Just infinite nothingness. I can't imagine anything scarier. I say this as someone who has dealt with disability for my whole life, chronic pain for about a decade, and as someone who has watched multiple family members die from horrible diseases. I think this life is all we get, and I don't see how you could ever want to cut it short, no matter how bad it gets.