I have definitely felt that way. I have attempted somewhat impulsively in very desperate states, and (spoiler alert!), those all failed. Other times I was a bit more composed and detached, and had planned things out well in advance, but then when the day came I either couldn't override SI, or something happened in my life that I thought I should deal with and I postponed my date.
There was one attempt that was a mix of both: I had a solid plan in mind, and when circumstances worsened, I gave myself a day to think about whether I was going to enact my plan or stick around another week to see if I could make any progress regarding my situation. The next day, I woke up, and I had this really strange feeling…I felt very calm and cool-headed, yet at the same time, I could feel all of my agony just coursing through my veins. I just knew that it was time. I wasn't sad or conflicted or even scared. I just knew, at the very core of my being, that I would die that day. It felt almost like a superior type of knowledge, too. I'm not religious, but I felt that God, the universe, or whatever forces might be out there were telling me that my suicide was exactly what I was supposed to be doing that day.
I took all the necessary steps, and throughout the whole thing I felt secure about my decision, almost happy, even. Almost like feeling exhilarated but serene at the same time. I remember looking up and thinking "this is meant to be". I even gave myself one last chance to back out and call a crisis line, and I wasn't even slightly tempted by the idea. I thought "no. I've had enough. It's time". I wasn't even afraid of the pain. I knew it was going to hurt, but it felt like the ultimate act of self-care: just please, please get me out of here so I can have some peace.
I reached the point in the process where I was *almost* past the point of no return, and I was still driven to continue, almost as if by an outside force. Then, suddenly, this guy appeared out of nowhere (not anticipated, and I still don't know how he got to me so quickly). He told me his name was "Franco" and asked for mine, and he even physically intervened. I don't like telling the story, because it sounds like something out of a movie, and I assume people will think I made it up, but I didn't.
I suppose I will never know whether I would have backed out at the last second on my own had "Franco" not appeared (it's possible), but I really don't think I would have, given the way I felt. I also think that the plan would likely have killed me. (Again, I can't know that for sure). I know "Franco" was trying to be a Good Samaritan, so I can't really fault him, but I do wish he had been elsewhere that day.
Since then (June 2019), I haven't managed to get back into that state. In December 2020, I made one more attempt that was of the impulsive, pain infused variety, and it really didn't have the same gravity to it, so I'm not surprised that it failed. Then I was in a psych hospital for 5 months, after which I just felt so depressed that I didn't have the will to do anything. Then the will came back with a vengeance, but it was the holidays so I figured I should wait, out of respect for my family.
I have now made preparations for another attempt (though not quite ready just yet), but I have no idea if I can ever get back into that (somewhat surreal) state. I still haven't accurately described what it is. It was kind of like a trance, but at the same time I could acutely feel all of the pain and desperation underlying my situation, and I could also think very clearly. Clear thinking and desperation don't usually go together, so I think it was a highly specific state of being, and frankly, I'm not sure I will ever be able to get back there. I don't think I can push myself there. When it happened, it just…happened. And it only happened ONCE in nearly two decades of rebounding suicidality and multiple attempts/imminent plans.