I played a very enjoyable CoC one-shot with my regular group, a free scenario called My Overcrowded Pineal Gland. Incidently, I recommend the adventure as a real departure from the usual investigate->library use->eaten by monsters CoC scenario, and it depends on some secrets to run as written, so if you think you might play it, avoid reading the Spoilers below.

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The characters are a PC having a psychotic break, and figments of his personality, each with their own motives and goals. Anyway, long story short, the PCs ended up taking part in a ritual with some cultists, and the result of the ritual was that my PC (an Elder Thing living in the unconsciousness of the psycho-PC) was going to be destroyed.

I rolled a psychic power to try to kill the cultist and failed, and the GM narrated my PC being drawn inexorably toward destruction. All the other PCs got a chance to do something. Then the GM asked me again what I'd like my PC to do.

I was sorta surprised. I tried to have my PC escape, but no-go. So, for lack of other options, I had the PC try to kill the cultist again, with his psychic powers. Another failed roll. We went on like this for a couple more iterations, and then the GM narrated my PCs destruction and the subsequent death of the rest of the PCs. It was a fitting ending to a fun scenario.

But it's nagging at me. Maybe it's my exposure to BW's Let It Ride rule, but I was totally unexcited by playing out the same 'psychic kill' actions/rolls for three rounds before the final defeat of my PC. I think the GM was giving me chances to win by making it an extended conflict, but because the conditions of the conflict weren't changing, I had this feeling of "get on with it already". This might've also been due to the fact that it was near the end of session, we all knew this was the final scene, etc. And it might've been because as an Elder Thing of unspeakable evil, I thought it was somehow a fitting end to the character.

But I was wondering, is there a Forgite take on this situation? Why didn't this 'zooming in' on my conflict work?

Cool scenario.

Yeah, I think you hit it on the head when you said it was the same doomed roll three times in a row.  There were no mechanical changes from roll to roll.  You felt like you only had one option, your psychic death ray.  Sure, you could have had other options, but they were obviously not... erm...  obvious.  Hell, I would have let you botch your first roll and then just give you a monologue of defeat, so that your doomed Elder Thing could at least go out with style (e.g., truly, you have been cast into the Void, but everyone who witnesses your true form has their minds sundered, and all commit suicide within the year, etc.).

I have a rule in any game I run, besides DnD (where this kind of thing is pretty much inescapable); never roll the same thing twice.  If you fail, it means you CANNOT win without changing the circumstances.