I guess it depends on how you define "ceased".

I'm specifically thinking of hypothermia patients and people who have had electroshock therapy. From what I've read, those who avoid brain necrosis lose the last few hours of their memory before the incident but are otherwise fine.

I don't think this is true. For example, imagine that I told you I had a magic bean that, should you eat it, will cause you to be instantly revived after death, in perfect physical and mental health; and that I will sell you this bean for $1000. Would you buy the bean ?

You're right, what I wrote came out sounding much stronger than I intended. The point I was trying to make was that there is no real "safe option"—the choices available right now are basically cryonics or rotting. And if you value your life at, say, $10 million, the expected value of cryonics is positive even with a pretty small chance of it working.