I imagine there are variables. I think it's kind of irresponsible to claim it's 100% safe if someone survives. That said, I haven't come across too many cases where people have had debilitating consequences. Although you have to also wonder- could they still post here if they had been that badly damaged? I kind of feel like the pro-lifers would be jumping all over it if long-term damage were common. That would play very much into their hands. Although, they may also not want to draw more attention to it as a method.
I imagine it depends on how far along the process has gone by the time it's interrupted and, how quickly it's reversed. This isn't scientific by any means but, SN kills via depriving major organs of oxygen. It seems to me like, the longer they go without but the person isn't dead- presumably, the more severe the results would be. That's just my layperson's view. That's not something we have complete control over but, I suppose we can try.
It troubles me also as, it's likely to be my method too. I feel like the chances of me being interrupted are slim. Hopefully, I'd have enough resolve not to call for emergency services. I went through 13 gallstone attacks without calling them. I hoped it was a heart attack initially. (After that, it was my reluctance to see a doctor.) I'm mostly worried about vomiting too much up. Especially if I'm unconscious and can't drink more. People have succeeded despite vomiting though. I don't know. I just think it's always going to be risky. We just have to try to mitigate the risks- getting an antiemetic, following the protocol etc.