Were you still in the ligature?
I've experienced something similar but I got out of the ligature. I had blacked out but did feel a certain awareness of what was happening. My body had started flailing but somehow I got out and my vision game back as I was storming out of the room. It was pure instinct that had taken over and I was fully invested that day. There was no doubt in my mind, I was ready to ctb but still, survival instinct took over in a way i never imagined possible. It was a very uncomfortable experience and my throat/neck felt damaged for months to follow. I'd bitten my tongue too and whilst it wasn't particularly nice it was the least uncomfortable aspect of the whole thing.
Part of me feels like those that succeed in partial may well have struggled and failed to get untied. Though I do believe some are able to succeed through sheer determination. I suspect under the very worst of circumstances with nothing holding them back. For example prisoners experiencing rape and exploitation whilst facing no potential way out.
As your body flaps and flails in the process of hanging its entirely possible to loosen the noose and come round.
Either way, partial and full hanging are not a nice way to go. For the bus catcher or those that have to find the body. Wouldn't recommend.