I have something similar in my will, too (I had to draw up my will and Advanced Directives in 2013, when I was - 32, maybe? - because my oncologist was so certain I was going to die from cancer at the time. Still here. Sorry, enemies!). But I also want cremation, with my ashes to go into the Bay in Maryland. And I absolutely feel you about knowing what it's like to not breathe. I have radiation poisoning in my lungs from 40+ rounds of thyroid radiation and then 6 radiosurgeries on my brain, so... breathing is hard every day. And it is terrifying, you're right! I don't wish it upon anyone! Hence why I'd want an "I'm not dead" emergency bell! ;)